My 2006 M35X vibrates when I got over 61 MPH to 80MPH. I had my wheels rotated and balanced. It made no difference. My mechanic thinks it might be the driveshaft? Although the universal joint looks good. Any ideas why this is happening? The car also veers to the right when I break, but I was told by infinity years ago that this was a defect in this model. Is it dangerous to drive with this happening?