SuperPro Rear Trailing Arm Lower Front Bushing Kit | 1990-2021 BMW 3 Series/Z4 (SPF2146K)1990 2021 BMW 3 Series Z4 Trailing Arm Lower Front Bush Kit by SuperPro As the OEM rubber trailing arm bushings deteriorate they induce undesirable characteristics into the handling of your vehicle. The trailing arm bushes stabilize the forward and aft movement of the axle. As these bushings wear they impart steering angles on the vehicle causing it to wander all over the road and make the vehicle subject to unintended and sometimes severe directional