Don't know what to say, CQ, but my blades also chattered on my new coupe and the only thing that seemed to fix the issue was to replace the windshield. Before that warranty service, I tried everything: Scrubbed the windshield with Bartender's Friend, made sure the blades were clean, even readjusted the blade angle so that they were at a 90 degree angle to the windshield. When I brought the car into the dealer, they essentially went through the same steps (including they have a machine that automatically adjusts blade angle...tells you they know there is a problem,) none of which worked; thus, the windshield replacement (noted in the forums as the final fix and again an indication that MB is well aware of this problem,) which mostly worked, but I still have a very slight chatter whne the raim is very light or misty. So, if the new blades don't work, bring the car in an let MB go through the paces until they replace the windshield.