Just to add, do check on the upper locating link as well, its the thinner arm in front of the wishbone. The ball joint often gives way on them, when the boot gets torn. I've had to replace them on two E53's already.

I check my rear wishbones by jacking up the car and grasping the tire at 12/6 and 3/9 and shaking. I found worn wishbone ball joints that way.

To check the bushing on the wishbone, you can check it visually while using a big screwdriver as a lever trying to move the bushing. Also check if that metal tube in the bushing the bolt passes through is still centered in the bushing. On two E53's I noticed that while the bushing was intact the tube was not centered anymore. This pulled the top of the hub inwards and resulted in excessive negative camber. Replacing the wishbone assemblies got camber back to spec again, both times.

__________________
04 X5 3.0i auto
03 X5 4.6is