clintster77

remember just because you only gain .02 seconds at the drag strip doesn't mean that that is all you gain.
better mpg, stop faster, and corner faster
add all those up and you are getting a good deal I think (I want one)

CutterWolf

Well Joe, you can always get forged internals and crank up the PSI

Hootna

I have the 4" and not 100% sure on the feel since I had it installed at the same time as most of my other mods but any weight you can save in the drivetrain without having a failure is a good thing.

That being said my initial experience was not good. If your car is dropped a 4" will make contact. I couldnt accelerate hard without feeling and hearing a grinding below the center console... Nice feeling through your arm

Took it back to the shop a couple of time's and got it back from the shop with the same issue. When I brought it back the last time to have the suspension installed I told them to make sure it clears and to take a frickin hammer to it if they had too.. anyway it is fixed with 0 vibration and 0 grinding..

Here is the instructions if you car is lowered. Note I did not have the UCA until the last time when they fixed it so I am sure I had a lot of issues under my car but not sure if the instruction's I had from them came with the additional instructions.

www.coastdriveline.com/NEW_Mustang.htm

ADDITIONAL INSTRUCTIONS FOR MODIFIED MUSTANGS
(vehicles that have been lowered or altered)
Lowered vehicles must have an adjustable upper 3rd link installed to correct the pinion angles. Factory transmission angle is negative 2.7 degrees down. The differential flange must be adjusted to 2.7 degrees up at ride height with car sitting on the ground. This is a must to eliminate vibrations in the drivetrain.
When installing your new 4-inch Coast Driveline aluminum driveline, three items need to be addressed. They are:
1) Unscrew E-brake cable bracket in rear of tunnel.
Slide over 2-inches and drill hole.
Reinstall bracket and cable.
2) Locate stamped metal stiffening plate located just past the rear of
transmission in floor tunnel. (It is 6-inches long and has a hole in it.)
Use a hammer and flat punch to knock in flat to tunnel.
3) At the very rear of floor tunnel there is a rolled lip where panels are

AmericanSpeed

I have the spydershaft. What shifter do you have? I have the MGW and being lowered on the steeda ultralite lowering springs, I could not keep my MGW at the shortest throw because there is not enough clearance. Keep that in mind, the lower you are, the more chance you may have a problem. The 1-piece definitely takes away the clunkiness of the stocker and will rev much more quickly. I do have a little more vibration if I get on it real hard, get up to a good speed, and then just let off the gas and coast in gear. It's nothing that is too bothersome though, just thought I'd let you know.

SirKnightTG

I have the dynotech from Brenspeed and since I did the indexing as was mentioned (thanks to Taco Bill's write up) I have no issues at all. I've had it for a good 1K miles or more so far.

miloman

I'm lowered and bought the Shaftmaster 3.5". If installed correctly using their instructions, but also TacoBill's, you will have no issues whatsoever. No rubbing, no vibrating. I agree with JimC, felt "lighter". Didn't really feel faster, just lighter. Maybe I'm weird. Anyway, definitely worth the $$$ for the aluminum d/s.