On 99-04 Cobras, we "hard-mount" the IRS carrier to keep it from moving around and for tire clearance. Geometry Adjustment - literally cut off all the suspension pick-up points and weld them back on to reflect the new geometry Kenny worked out on the computer. Included in the geometry change is a Rear-Steer Hardware kit (a KB exclusive) that helps reduce the unwanted effects of rear roll steer, which can be pretty unsettling in the middle of a fast turn. The combination of converting to Tubular Control Arms and Coil-over Shocks takes off a substantial amount of weight from the rear IRS assembly
To Read more go to https://kennybrown.com/pages/kenny-brown-csr-cobra
Note: A Good Clean Core is required for Modification.