BMW E85 Rear Shock Replacement – 2002-2008 Z4 – All Models ↗
Z4 rear shock swap. The fiddly part is the soft-top storage floor in the trunk and its plastic clips. After that: wheels off, the trunk liner peeled back to reach the top mounts, the hub jacked up to unload the shock, the 18 mm lower bolt off (100 Nm on refit) and the 13 mm top nuts off (28 Nm). The article recommends adding shock-mount reinforcement plates.
Tools mentioned: 17/18 mm and 13 mm sockets, breaker bar, trim tool, floor jack, torque wrench