Millway | Rear Upper Control Arm – BMW E36, E46, Z4 | 7075-T6 AluminiumRear control arm for all E36 E46 Z4. Motorsport Uniballs. They are machined from billet 7075 T6 aluminum. They replace the original location of the spring. And therefore can only be used with coilover rear. Drop Links for the sway bar are Included. These are mounted directly to the control arm in line with the inner and outer joints for optimum performance. To fit the swaybar links you need a swaybar with holes. OEM swaybar will not fit without