BMR 15-17 S550 Mustang Differential Bushing Kit (Polyurethane) - RedMinimize wheelhop and enhance the rear stability of your S550 or S650 Mustang by decreasing differential movement with polyurethane differential bushings from BMR's suspension. Polyurethane is a synthetic polymer with many properties that make it far superior to OEM rubber for bushings. Polyurethane deflects far less that soft rubber, and it doesn't breakdown from exposure to petroleum products, road salt, ozone, and other elements of the harsh