204, C63 exhaust hits underside crossmember
 

My 2011 C63 when hitting bumps or bridge/overpass
ridges the exhaust is hitting the aluminum bar that crosses between the tailshaft and the differential. It is very annoying and embarasing.
I have loosened the clamps and raised both pipes up and then tightened the raised pipes only to have them drop again.:confused:
I understand the normal C-class cars also have the same problem. Has anyone else had the same thing happen and how did you resolve the issue?

Thanks for any guidance....