Bushing Kit, Rear Upper Control Arm, InnerEnhance the stability of your Pontiac G8 with a Rear Inner Upper Control Arm Bushing Kit from BMR Suspension. Polyurethane is a synthetic polymer that has many properties that make it far superior to OEM rubber bushings. Polyurethane deflects far less that soft rubber, and it doesnt breakdown from exposure to petroleum products, road salt, ozone, and other elements of the harsh undercar environment suspension bushings live in. BMRs polyurethane Rear