hopfully i can clear up some questions and will let some people know about how things work. ill give pictures of each brand and the differnt models each company offers. i will also go into detail on adjustments, features, price, customer service, turnaround time, and overall appeal/quality of each shock.
to get started, we must know about the adjustments/features on the shock.
PRE LOAD- this is the spring tension adjustment. it controlls the overall stiffness of shock
RESIVOURS- cylindrical "storage tanks" that are partially filled with oil, and partially filled with compressed nitrogen gas with a diaphram seperating the two. ads extra oil capacity for more controll and less fading of the shock.
COMPRESSION- this adjustment is located somwhere between the body and rezzie of the shock. its basically a glorified needle valve that controlls the amount and the speed of the fluid that is going out to the rezzie. Some Elka shocks offer High and Low speed compression adjustments. these will controll the shocks SHAFT speed. the high controlls the high speed impacts while the low speed controlls the slower less noticable bumps. this adjustment is probably the most needed as far as fine tuning your shocks.
REBOUND- this adjustment controlls how fast/slow the shock shaft returns to its extended position.
CROSSOVERS- these are small "ring" like spacers between different springs. these will only be found on multirate shocks. they controll the progression of the shock.
SPRING RATES- some shocks feature multiple springs. this is called a multirate shock. the theory behind this is that the upper springs are softer and will take the impact of smaller bumps, while the main spring will take the beating of the large jumps and hard landings. again, this is adjusted using differnt crossovers.
Custom Axis
Adjustments-Preload, Compression, Rebound
Features- CAD/CAM technology, 5/8" diameter shafts, race proven suspension fluids, "live spring" design. all this ads up to make one extreemly adjustable and tunable shock.
Price-$895-$1325
Customer Service- overall good customer service, willing to revalve if not setup properly the first time.
Turnaround- ranges from a week to 3 weeks, depending on time and demand
Appeal- Axis shocks are state-of-the art shocks. fully designed on CAD software and machined out, their looks cant be beat. quality parts and service go into each shock. Axis is a division of Penske Racing, a leader in automotive suspension.


PEP
Adjustments- preload, compression, rebound
Features-quad rate, ZPS, BIG rezzies, race proven, chrome bodies
Price- $595-$1695
Customer Service- this is where PEP falls behind. because of there extreem waiting list and only 2 guys making the shocks, getting a revalve or service can take some time
Turnaround- 3 weeks and up to 3 months
Appeal- with their chrome bodies and multi colored springs, they stand out in the crowd. they also preform just as good as they look with many of the top GNC pros riding on PEP. they have been in the buisness ever since quad racing began. the quality of these is top notch from the spherical bearings to the internals.


Elka
Adjustments- preload, compression H/L, rebound
Features- quad rate, SSD, innovative designs, cool anodized red parts
Price- $450-$1295 TRACK system will be more
Customer Service- Elka is known for their excelent customer service and helpfull people.
Turnaround- 1 week to 3 weeks
Appeal- yet another great looking shock. the anodized red is different from anyother in the business. however, looks can be deceveing. because Elka almost mass produces shocks, each shock mignt not get the "care" and attention that Axis, PEP, and TCS provides. this is probably the main reason why many people have to send their shocks back for revalving or re-springing. but regardless, they make a good quality product.




TCS
Adjustments- preload, compression
Features- tripple rate, SCS, shim style valving, simple yet effective design
Price- $650-$975
Customer Service- from Lake Elsinore, CA, TCS provides excelent customer service. owned and opperated by Todd Davis, this company knows how to tune your shocks. if you dont agree, take them back because theres a 30 day revalve guarantee.
Turnaround- 1-4 weeks, depending on the season and avalibility
Appeal- TCS shocks are very easy on the eyes

FOX Racing Shocks
Adjustments- "preload", compression, rebound -> C/R only found on the Evol shocks
Features- uses air pressure to controll the firmness of the shock, infantly adjustable, new doubble piggyback style
Price-$695-$1300
Customer Service- well, Fox is big in the Downhill Offroad Bike industry with many different models avalible for bikes. also into full off road buggy/truck suspension, and iv never heard anything bad about these. so i think its safe to assume that their service will be just as good as their product
Turnaround- because there is no specific valving, and you do all the fine tuning of these shocks, these can be at your door as fast as the UPS man can bring them!
Appeal- the look and technology of these products is outstanding. this could very well be the future of ATV suspension as we know. multi spring rates and the valving methods for regular shocks date back to the '20s. its time for change! and Fox is just the company to do this



Ohlins
Adjustments- preload, compression, rebound
Features- made in Sweeden!, years of shock experince, dual or single rate springs, high quality components
Price- $750-$1150
Customer Service- Ohlins now has a handfull of distributers and small manufacturing plants here in the US. although you wont be directly connected with their facilites in Sweeden, your shocks will be tuned and refined in the US. not many people riding on Ohlins since the 250r days, Dunk is the only one i can think of off hand.
Turnaround- usually fast, taking with in 2-4 weeks
Appeal- Ohlins hasent changed their look in a long time. and why should they? the gold anodized rezzies and intense yellow springs make them look race ready, and they are.


Motowoz
Adjustments- preload, compression, rebound
Features- new single Titanium Spring, large lines to rezzies for maximum fluid flow, advanced CAD designed VSV valving, "tripple" seal system.
Price- $1070-$1750
Customer Service- Motowoz has an awsome valving program with lots of new technology in the shocks. im sure they will help you out with all of your suspension needs
Turnaround- Sadly i cant answer this question, because i havent talked or seen anybody run these shocks
Appeal- another awsome looking shock. one with looks as good as performance. Motowoz is now offering a lineup of a-arms (standard and long travel) as well. these are sure to please even the most critical rider.
For pictures, please refer to the Motowoz website. amazing looking products
http://www.motowoz.com/photos.html
Works
Adjustments- Preload, compression (H/L), rebound
Features- ZPS,new 5/8" shafts, checkball valving, Black Widow,"G" Series, Pro Series, and A-T Series to match any riding style
Price- $320-$1050
Customer Service- good customer service with a revalve opperation if your not satisfied with your shocks the first time around.
Turnaround- quick times using a large manufacturing facility. usually 1-2 weeks
Appeal- their new designs are like nothing we've seen from Works. a new dual line rezzie and also the Black Widow series. in addition are the gold anodized rezzies, black bodies and red, black and white springs.



Progressive
Adjustments- preload, compression (H/L), rebound
Features- new "6th-sence" valving technology, Control Valve Technology, position sensitive damping control. very advanced technology. Five controls independently adjust bottom out resistance, low speed compression, high speed compression, rebound, and preload.
Price- $alot$, havent seen a price yet, but im sure its not going to be cheap!
Customer Service- because these shocks are soo adjustable, they dont need to be revalved. thus, almost eliminating Customer Service. but PS has been around for a good number of years and would help you out in geting a great set of shocks
Turnaround- since they have no specific valving (at least to my knowledge) they could simply be shipped directly to you.
Appeal- perhaps the best looking out of our line up. large piggyback rezzies which get their fluid from dual compression adjustments look trick. deffinently should not pass these up on your search for a better suspension!

as you can tell, ading a set of good aftermarket shocks to your machine will greatly enhance the ride quality. its a night and day difference compared to the stock units. but, theres more to it then just shocks alone.
next we will take a look at a-arms.
as far as the design of the arms is concerend, there are only two. standard and long travel. the standard uses a stock lengh shock, and the long travel uses a slightly longer one. the only real difference between the two (becides looks) is the ease of tuneablity of the long travel. because it uses a longer shock, you can notice the shock settings better. concequently, when you make an adjstment on your shock (ex. increase the compression) you will notice it slightly more they you would on a standard travel arm. the long travel arms also offer a slightly better ride quality. close to the same can be acheived with standard arms, but will take alot more skill to adjust and more fine tuning.
in the world of long travel, there are straight arm designs, and gull wing designs. the straight arm design will have the shock mount under the main tube on the lower, where as the gull-wing design droops down allowing the shock mount to stay on top of the arm. there is no real advantage to the gull wing design, as the shock mount point will be in the relative same location as the straight arm. the key to making a suspension work properly is the leverage ratio. the same leverage ratio can be achieved using either style.
heres some info i wrote up along time ago:

lets set up 3 points. we'll call the frame mount point A, the shock mount point B, and the spindle mount point C. the first arm is a basic gull-wing design. the second is a straight arm (Laegers,JB), and the last would be the "loops". i have drawn with the best of my abilities in Paint a light blue line representing a shock. the shock is the same length in all 3 cases. now also note that the mounting points are the exact same in all 3 cases. so if the points are the same and the ball joint position is the same...then what makes a gull-wing design any better?
"there is a point behind it and its usually to run a longer shock which increases travel."
the straight arm can run just as long of a shock as a gullwing arm. notice the mounting of the shock remains undernieth the arm. thus...giving room for a longer shock. however, laegers feels that a shorter shock runs better, but houser on the other hand uses a 18.5" shock on a straight arm design. all they did is change point B down farther on the tube.
"the gullwing is designed to help lower the ride height " in the drawing above, you will see a very fine yellow line running through the red arm. it represents a straight tube design. and also note taht the mounting hole is below the yellow line allowing you to run a longer shock as i stated before. now with point A and C being in the exact same place, how could you get a lower ride height? but maybe my drawings are not representative of what a gibson a-arm really looks like, and maybe their bends do alow for a lower ride height.
i just dont see a real advantage on the gibson arm from a design standpoint. the only way you could tell which one you like best would be to ride both setups and see which one handles better for you. either way, you wont go wrong. both are made to high standards with high quality parts!
the quotes i put in there were objections that another member made in regards to the gull-wing design.
again, i will put together a list of terms that you should know when dealing with A-arms. (these definitions can be long, but are critical to set up any good suspension)
LEVERAGE RATIO- this is a ratio of wheel movment to shock shaft travel. the ideal ratio is 2:1. this allows the best ride quality and the most tuneability. i believe that this is measured from ball-joint or hiem joint on the end of the arm.
SHOCK MOUNT- the shock mount is simply the position of the arm that the bottom bolt of the shock mounts up to. it should be well tied into the arm so the load can be distrubuted evenly, not just some tabs welded to the tube
WIDTH- as you can imagine, this is how wide the arms will make your quad. they come in +1 +2 +3, and all sizes inbetween. many people are confused by how wide they will really make your quad. simply put, the "+2" label given to the arms means that it will add 2 inches PER SIDE, not over all.
BUMPSTEER- bumpsteer is the tendency of the wheels to toe-in when the arms go through their travel. it is most commonly found when landing hard (making the arms use up all the shock travel) or when the front end is off the ground (having the shocks fully extended). this can be fixed by seting up your front end properly.
CAMBER- Camber is the angle of the wheel relative to vertical, as viewed from the front or the rear of the car. If the wheel leans in towards the chassis, it has negative camber; if it leans away from the bike, it has positive camber. The cornering force that a tire can develop is highly dependent on its angle relative to the track surface, and so wheel camber has a major effect on the track holding of a quad. It's interesting to note that a tire develops its maximum cornering force at a small negative camber angle, typically around neg. 1/2 degree.
CASTER- Caster is the angle to which the steering pivot axis is tilted forward or rearward from vertical, as viewed from the side. If the pivot axis is tilted backward (that is, the top pivot is positioned farther rearward than the bottom pivot), then the caster is positive; if it's tilted forward, then the caster is negative. a slight positve caster is wanted, and comes from the factory like so.
TOE- This is simply the condition of the wheels relative to each other. when a pair of wheels is set so that their leading edges are pointed slightly towards each other, the wheel pair is said to have toe-in. if the leading edges point away from each other, the pair is said to have toe-out. the amount of toe can be expressed in degrees as the angle to which the wheels are out of parallel. toe in is always wanted, and toe out is never a good thing
because there are so many brands of A-arms out there, i will leave that decision up to you. there are soo many of them to choose from, it can be confusing and hard to find the right one. keep in mind that just because an arm uses a longer shock, dosent mean it will ride better or have more travel. you should try and stick with a 2:1 leverage ratio arm (when dealing with long travel). i personaly dont care for Heim Joints on the lower arm. the spherical ones in arms like Walsh and RPM seem to be designed correctly, but the exposed ones found in arms like Fireball (Janseen, Denton, and SandDragon arms) dont really appeal to me. they claim a greater strength, but the 22,000 puond force rating isnt in the vertical direction, but rather the horizontal direction. AKA the pulling force. heres a crude drawing to give you a better understanding.

again, this is my personal perfrence. keep in mind that the Heim Joints are much more susceptable to dirt, water, and grime getting inside them because they offer no protection as oposed to Ball Joint boots. this causes extreem premature wear and tends to make them fail faster then a quality ball joint.
with this being said, im finished with my small tutorial on suspension. it is clear that aftermarket shocks; no mater if their top of the line Axis, or basic Ohlins will drasticly enhance your machines ride quality. this leads to easier riding which in turn leads to faster lap times at the track, or a better, more enjoyabe day at the dunes
i think that it would be a good idea if members with aftermarket suspension were to make a brief post about their setup
*prices and availibity are subject to change with out notice*
BUT WAIT, THERES MORE
as per the request of some members on this site, i will be giving some tips on setting up the suspension. (and they're free!
well lets get started shall we? we're going to be looking at the setup principals as noted above (caster, toe, etc..) the first thing to look at will be seting the proper ride height. for MX, your going to want the back frame rail where the pegs mount up to be 7" off the ground. then, take a measure 5" towards the front of the bike on the lower main rail. this reading should be 7 1/4" meaning for every 5 inches you move up towards the front of the bike, it should raise 1/4". and dont forget, these and all other measurements/adjustments must be done while seated on the quad. this is a 2 person job, so grab a friend or your dog. wait, scratch the dog, intense training would be required
once you have that set up, you can begin to adjust your other features. ill leave that one up to you. adjustment styles are different on different styles of arms. but ill give you some measurements for a baseline.
Camber- MX 2.5-3 degrees negative camber(top of the tire leaning toward the center of the quad). Trail riding and desert, negative 2 degrees.
Caster- MX 5.5-6 degrees positive, trail riding and desert 6-6.5 degrees positive.
Toe- in an 1/8-1/4 inch.
to simplify caster (and not many arms have caster adjustment), the top ball joint/heim should be 5/8" set back from the lower one. this would be from a top down view. again, this is just a baseline reading, and should be fine tuned.
compression and rebound settings are completly up to you. different riding styles and condtions make it extreemly difficult to pin-point which setting will work best without being there. but for a general statment, MX riders will want a rather stiff compression setting, and a some-what fast rebound. XC racers will need soft compression adjustments to soak up all the bumps, and a medium to quick rebound. desert....well, im not gonna lie to you, i have NO CLUE? but i could only assume somewhat soft for compression. if your into TT or ice racing, then you will need stiff compression, and slower rebound. and ovcourse being low is another must.