I had the same problem with my car, c220. Turned out the engine mounts were the cause. In my case, one was worn and the other had collapsed, which led to unbearable vibration. I think you also need engine mounts.

I'll be honest be prepared to spend lots of money on repairs for your car.
My C220 has taken over $15 000 IN REPAIRS! in the last 5 years, and now i have a tranny malfunction beggining to happen.

My '98 BMW 528i in the mean time, has only needed 500 dollars in repairs, and that repair was a water pump. Rest has been regular maintenance.

This is my second bad experiance with mercedes, I'm starting to wonder how reliable most of there cars still are. Or do is my BMW just lucky....