I have a E430 4matic, I changed the front pads and rotors, new tires and high speed balance but still have vibration around 50 and when I apply the brakes over 40, vibration occurs, does anyone know why?

 

I am having the exact same problem. Have you suspected any problems with the transmission? I know mine has been acting funny the first month after I bought my car. I just haven't had time to let my car sit in the shop for an indeterminate amount of time. It is a good thing I bought it CPO, so it has that Starmark warranty for a year. I am taking mine in for a check-up tomorrow...I, myself, have a humming upon disengagement of the accelerator at high speeds and around 15 to 20 MPH. There is a 'clunking' sound coming from the rear end if I let go of the accelerator and quickly re-engage it, especially at low speeds. Hopefully, yours doesn't have the problems mine has...but have the stealership/qualified mechanic look at it.

 

Re-do tire balance again. and after 500 miles one more time.

 

Had a similar problem with my 99 e320, shifting awkward and clunking noises at low speeds. Had the car in for an oil leak and had them check the transmission. The control unit had failed. Leak and transmission repaired under starmark extended warranty.