Ok, whenever I get to 45mph+ my car vibrates real bad. The door panels shake and my window clanks against the door, and it's almost impossible to look out the mirrors. I had my front motor mount replaced at a local shop, and this only helped the problem a little. Could this be from the rear motor mount? And if I were to get a set of mouter mount inserts, would that fix the problem? Any help would be appreciated...it is starting to drive me nuts.