The Eibach Pro-Kit 3594.140 is a four-spring set of progressive-rate lowering springs for the 2003-2004 Ford Mustang SVT Cobra, covering both the coupe and the convertible with independent rear suspension (IRS). Published specs describe a drop of about 1.0 inch in front and 1.4 inch in the rear, which gives the car a tighter fender gap and a more aggressive stance without a harsh ride. Owners on user forums say ride quality stays close to stock while the car holds its line better in corners.
Compared with stock springs, this kit targets the handling losses that matter on a spirited drive: body roll in turns, squat under acceleration, and nose-dive under hard braking. Because the spring rate rises as the spring compresses, the car should feel more controlled under load. For a Cobra owner who wants 2003-2004 SVT Cobra IRS lowering springs, a progressive-rate set like this is a practical street and autocross upgrade. Searchers looking for an SN95 Cobra coupe or convertible progressive lowering spring kit will find this part matches that description.
The manufacturer's install guidance says to keep the original spring isolators, dampers and tubing and reuse them. Owners on user forums report that removing one isolator per spring adds a small amount of extra drop, but that is not part of the manufacturer's instructions.
No. The manufacturer lists this kit for the 2003-2004 Cobra coupe and convertible equipped with IRS. No other Mustang trims are listed for this part number.
Yes. The manufacturer recommends checking and adjusting camber, caster and toe, along with fender and tire clearance, brake line clearance and ABS sensor position after installation.
The manufacturer's install sheet calls for a qualified mechanic experienced with suspension springs, and recommends a hoist and safety stands with the wheels blocked. Other fitment references describe the job as moderate difficulty, needing basic shop tools and a spring compressor, and taking about four hours. Mark the springs by their 001 (front) and 002 (rear) suffixes, and install each with the Eibach logo right side up. Owners on user forums say seating the bottom front isolators can be the fiddliest step, so lubricating them helps. After reassembly, recheck the alignment before driving.
