[BaseM3]

Driving over bumps I hear a clunking from the front drivers side. Found this brown crud in the top of the strut tower. Looks like something is deteriorating under the top strut bolt. The passenger side is doing the same but not as bad. 2009 3.0 with 61k miles.
I've had a noise similar to this on a e39 and it was the top strut bearing. Does the X5 have the similar set up? The realOEM reference looks like just a top cap of some sorts.