From what I understand this is a common failure. If you get them replaced I would at least consider using the Meyle HD bushings.

http://www.meyleusa.com/BMW-X5-X3%20...%20Bushing.pdf

The bushings themselves can be pressed out and replaced but it just depends on the shop or mechanic as they will probably just replace the entire arm with the bushing already installed.

Best of luck.

k