Lowering a Mustang upsets the relationship between the steering rack assembly and spindle. The rack gets too low and the tie rods are forced upwards at their outer ends, introducing bumpsteer. A bumpsteer kit spaces the outer end of the tie rods downward, restoring the proper geometry between spindle and rack--a straight line. Maximum Motorsports offers several bumpsteer kits to accommodate various combinations of chassis and suspension arms. Expect retail pricing between $140 and $150.