Update: replacing the two rear sway bar bushings (PN: 33556756151) as suggested by @njaremka works. It only cost me $28 after tax from the local dealer and took less than 30 minutes to replace.

Hi all, my R60 JCW has 120k miles on it and recently has developed squeaking noise on the rear end when going through bumps or on harder braking. I can hear the same when pushing hard on the rear, but just can't figure out exactly where it's coming from and which part needs to be replaced. Can any of you throw some insight here? I've recorded a video if that helps. Thanks in advance!

 

Squeaking related to going over bumps or dips would typically be the rear sway bar bushings.