Mine is 2006 X5 3.0i 6spMT with 140K miles...
In the video below (air suspension), this youtube fellow had to undo the tension on the REAR suspension to check the REAR ball joint:
https://www.youtube.com/watch?v=b6Pt8NDYWm4
I wonder what you guys do...do you undo the big bolt to the BOTTOM of the rear shock to undo the tension before checking?
When did your REAR ball joint goes bad? In my 1998 528i, the REAR ball joint went south at 120K or so...