hello mate there is a mod that hatherway racing do to the rear beam.they mod the points were the rear arm joins the beamso u can lower the car and have very little camber also giving u a bogger foot print of the tyre on the road and ive been told that it transforms the drive of the motor with more traction and less breaking loose of the rear end and better tyre wear.it cost more than the shims u have been asking about( bout 100 notes more) but its propper good.im gona have it done to my 3dr in jan and im running 245/35/17s on mag touring car split rims rims