Differential Vibration Absorber

[drift838]

Have noted that in the parts list, all E46 6 cylinders should come with a vibration absorber attached to the final drive as in this attachment (part no. 5).

http://www.realoem.com/bmw/showparts.do?model=BN12&mospid=47615&btnr=33_1185&hg=33&fg=05

But I peeped at many E46 M54, but didn't spot this part.

Anyone has any idea what this does? Does it help refine driveline quality?

Thanks