AKG Motorsport Rear Subframe Bushings, Aluminum – E46, Z4Product Description These BMW E46, Z4 Aluminum Rear Subframe Bushings eliminate all subframe movement for effective power transfer through the rear end. Rear subframe bushings are also the first step in maintaining proper rear end geometry and alignment. The stock rubber subframe bushings deflect as torque moves through the drivetrain, allowing the entire subframe to move. Eliminate rear subframe movement and start dialing in rear end geometry with