Ta,
From what I have read and other BMW owners I have talked to, the springs, struts and bushings start to wear out around 80k miles if not a little sooner. The reason really relates to how good and tight the suspension setup is that BMW engineered from the factory.

My suggestion would be to look into either replacing with new OEM struts, springs and bushings if you want to retain the factory feel or do what a lot of folks have done with their cars and upgrade your suspension set up to H&R springs, Koni or Bilstein struts...there are a slew of different aftermarket setups out there.

Personally, I've changed my Z3's suspension to the H&R/Bilstein setup and love it. I'm looking to upgrade the anti-roll bars and the bushings on that car soon as well.

The X5 is due for the same change, but haven't decided if I'll go back to OEM or go aftermarket...it's going to be a little more time before I can get to it.

Hope this helps some....

__________________
-Mike
2001 X5 4.4i
2000 Z3 2.3