The two primary functions of sway bars are to control body roll and to determine the understeer or oversteer behavior of a vehicle. Stock sway bars have low torsional spring rates because they are manufactured from small diameter bar stock or tubing. BMR Suspension?s SB043 front and rear sway bar kit was designed by factoring in the vehicle weight, application, motion ratio, coil spring rate, and adjustability requirements. Manufactured from heavy-duty 35mm (front) and 25mm (rear)DOM steel tubing, the SB043 is cold formed to better resist torsional fatigue and retain its “memory” far longer than the hot-formed bars used by many competitors. The sway bar is CNC-formed for exact manufacturing tolerances and repeatable high quality.Thrust washers are welded to the front bar to locate the sway bar bushing mounts. This is critical as it properly locates the sway bar and prevents lateral movement during hard cornering maneuvers The SB043 attaches to your S550 Mustang with polyurethane bushings, reducing the deflection from the stock rubber bushings. These bushings are molded from 88-durometer, low-deflection, polyurethane, and are internally fluted to keep grease in the bushing.