I'm wondering if someone has any advice regarding a vibration I am having in my 2007 E63 AMG. The car vibrates when I hit 30 MPH and continues until around 60 MPH, at which time it is less noticable. The vibration can be felt in the seat and floor. I've had the car in to the local Mercedes dealer five times and so far they can't seem to fix the vibration. To date, they have had it aligned, all four wheels straightened or replaced, all four tires replaced and most recently, the engine mounts replaced. It's currently in the in the shop for the fifth time and now they mentioned that it may be the flex disc and they are in the process of replacing that. Any thoughts would be greatly appreciated. Thanks!