I have a 2019 c63s and recently lowered it on h&r sport springs and did 15mm rear and 12.5 front which I saw on multiple threads that most people run. But my rear is rubbing quite a bit on bumps. For those who lowered with 15mm, are you rubbing as well?

 

Remove the spacers and see if the rubbing goes away. Could be different wheel offset, tire size, etc.