The vibration became so annoying I just took the car to mercedes to have it looked at. I was expecting a large bill of several hundred pounds sterling. (i'm in London).

What they found was even more annoying.

Despite having the wheels balanced twice before from two different local tire dealers, all 4 wheels were out of balance. The worse one was the new tire, that I had the dealer put on because I thought this was the problem. It was overweighted by 140grams. ( over 4 oz) I even watched the dealer balance the wheels and register the wheel as being balanced on the machine. The other 3 wheels were also overweighted by between 110 and 80grams ( 3 and 2.6 oz)

Mercedes only charged me 35gbp ($60usd) for the complete balance. The problem has now been completly fixed. The local dealers charged me 28gbp ($50usd) for each balance and screwed up each time. I should have gone to the mercedes dealer right from the start!

So as a note to those of you with what could be poorly balanced wheels. Take your car a reputable tire dealer. Preferably Mercedes. The smaller local dealers may be cheaper but are likely to have balancing units that are incorrectly calibrated like the two local dealers I used.

Cheers
Aaron.