Not a Benz, but my 02 VW Golf TDI 5 speed will do 114mph with a full load. Weight isnt too much of a factor for top speed, so I like to think the car riding lower allows it to have less lift.

Fastest I have gone was in a German spec 2001 745i (really cool, short wheelbase V8 without a sunroof). I did the math a while ago and it was about 130mph. I lost the nerve to go faster as the car wasnt mine, and I wasnt in Europe.