I have a '86 190E 8V that has a vibration in the steering wheel at around 40mph, then at 65mph and above theirs this roaring (not loud) vibration that can be felt in the seats and the arm rest. The car has 190K+ miles. The front and rear suspension has been repaired as needed by Mecedes techs. (ball joints, bushings, idler arm, etc.) I replaced front struts. New tires mounted, balanced. Four wheel alingnment was preformed at Mercedes dealer. I'm suspecting maybe the driveshaft flex disc's and/or support bearing assym. may be the problem.