LarryBible is right on
I purchased a set of Dunlop SP Sport 5000 for my '01 E430(purchased at NTB) and had them balanced 3 times. Still had vibration and had NTB swap the out for a set of Michelin Pilot Sport A/S. Balanced an additional 2 times, by now NTB has practically destroyed my wheels, and finally gave up on NTB. Did some research and went to Butler time. They use a Hunter wheel balancing http://www.gsp9700.com
system followed by an on-car highspeed wheel balancing. I could not believe the difference it made. It is a must if you are experiencing vibrations.
My new rule of thumb, use a good shop for installation and balancing of tires for your Mercedes.