This is the front rubber mount for the rear differential in the E46 M3 and Z4M models. The differential is mounted with three bushings - one in the nose and two in the rear cover. Since these are rubber bushings they have quite a lot of deflection. Over time, and with more torque and grippier tires, the deflection gets worse. This bushing is pressed into the front of the rear subframe. A Genuine BMW part. Best if used with fresh rubber mounts in
the back diff cover.This piece is also available in a
performance urethane material or included in a set of fully
solid aluminum mounts. Either will be an upgrade over the stock rubber as any reduction in deflection will be an improvement in performance and longevity.
BMW Fitments: 3 SeriesE46 (99-05) > M3
Z SeriesE85 / E86 Z4 (03-08) > Z4 M