what kind of rear suspension does a 2003/2004 svt cobra have.

One would think a solid axle setup, like the regular stangs, but I believe it actually has an IRS (Independent Rear Suspension) setup, very similar to the MN12 Thunderbird (89-97). I would look on google, but I'm too lazy.

IRS, for sure. Gay. You get above 500-600Hp you need to swap to live axle anyway

In 1999 the SVT Cobra was the first Mustang to get an Independent Rear Suspension. The design was somewhat of a compromise because it had to bolt into the existing mounting points for the solid rear axle. Thus the IRS is mounted using only 4 very large bolts. It utilized an all-aluminum center section similar to that of the Thunderbird, but those were the only shared parts to my knowledge. Control arms were all aluminum while the rest of the carrier assembly was welded steel tubing. Gear ratio was 3.27:1 and it used 28-spline axles. In 2000 the only Cobras made were Cobra Rs which received 31-spline axles and some additional bracing on the IRS not found in their lower-horsepower siblings. The 2000 SVT Cobra never made it to production due to horsepower issues. 2001 saw the return of the Cobra and its IRS basically carried over from 1999. In 2003 the SVT Cobra took a HUGE performance jump. This meant that the IRS from the 1999/2001 was not up to the task of handling 390 horsepower. Larger 31-spline half-shafts were added as was additional bracing to the IRS, some as carryover from the 2000 Cobra R. This cured some of the wheel hop problems, that were inherent in the previous version of the IRS; however, it did not cure all of the woes. Gear ratio went up to 3.55:1. Compared to the GT's solid axle the IRS is about 75# heavier and much more complex. It provides a better ride and slight handling improvements over rough surfaces when comparing stock for stock; however, it is extremely sensitive to alignment and drivehsaft, half-shaft and differential orientation. All parts must be indexed prior to removing them or vibration at high speeds may result. The solid axle suffers from serious suspension bind because of it's upper rear control arms. They are a compromise design which makes the upper rears provide rotational as well as lateral axle control. Thus they do neither job well. To get the best handling out of the stick axle requires the use of a torque arm and either a panhard bar or a watts link. A company called Steeda also makes an excellent 5-link setup that I use in my racecar. It is lighter and offers a wider panhard bar than the normal Torque Arm/Panhard bar setup. The 5-link does have exhaust clearance issues though and either the 5-Link II must be used or if using a series 1 5-link you'll need to use dumps or a custom exhaust.

the SVT Cobras from 1999-2004 are all IRS suspensions.

Me personaly I like the IRS in my 04. I find it handles nice in the corners. I had to upgrade the bushings and add a pumpkin brace, but other than that it is nice. I dont see having to put a straight axle in at 500 HP.

Def dont need a live axle swap at over 500 RWHP as stated earlier. Do a lil research and you WILL find alot of 03-04 Cobras running way over 500, myself im into the 600 RWHP range and have not had an axle issue yet. Heres just a lil example http://www.svtperformance.com/forums/pics-videos-buffet-149/608247-1104rwhp-e-85-though-auto.html

What is the significance of that deck lid? My 04 gt has the same one. I've been searching trying to find another car that had it.

what do you mean by significance? and are you refering to trunk lid? i know stupid questions but just so i dont give you the wrong answer haha

Yes the trunk lid is what I meant. I apologize

The trunk lid is the same as every other 99-04 Mustang. The spoiler is unique to 03-04 Cobras.

IRS

Really because I've never seen another one like it? On all the other mustangs from 99-04, they have the spoiler that is separate from the trunk lid. Like the one on the red car at the top of the page, my car has the spoiler made into the trunk lid.

the spoiler is actually bolted on to the trunk lid it is a separate piece. from the picture it does look molded. but yes it is a cobra unique spoiler. you can fit them on any mustang trunk lid from 99-04

Interesting. Well mine is all one piece.