Take a look at your sway Bar bushings and where they sit on the subframe, and the sway bar itself where it goes thru the bushing.

In my case, the salty roads of New England caused the area the bushing sits on to rust away...its not very solid to begin with AND the sway bar itself rusted away inside the sway bar bushing to the point it no longer fit snugly in the bushing... Please have a look.

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'03 530i - manual swapped - 425k miles
'06 325Cic auto 115k
'05 X5 3.0 auto 158k
'99 E39 528i 5-speed 130k