My 2017 M2 (non LCI) started doing this clicking noise (on top of my front window) after 25.000 miles... Today it did what was described in this post and I did not hear it again...let's hope it stays this way. Never imagined it could be this that caused it
I don't have a M2 comp, but now I'm happy I sometimes read in the M2 comp section
I used this...
