Bump stop?

[Paul Rice]

My 2010 E89 has an annoying knock at the off side rear of the car, sounds a bit like an exhaust knock but on the side of the car where the exhaust is no where near!
Looks like its a kind of bumpstop that is showing its sign of age and moves when it shouldn't.
Has anyone had this problem and what its actually called (think it may be a vibration damper?)

 

[Delk]

I dont know Z4s but that looks like a vibration damper weight to me. Sometimes they are used on exhaust and other items to reduce vibrations. Just a weight with a rubber bushing inside to change the harmonics.

 

[Paul Rice]

I dont know Z4s but that looks like a vibration damper weight to me. Sometimes they are used on exhaust and other items to reduce vibrations. Just a weight with a rubber bushing inside to change the harmonics.

Thanks for the reply, Think i will try taking it off and see if any different