hey i have a 1998 sc400 and i have a a bit of a bumping problem. When i hit high speeds like 60 or 70 there a bumping feeling in the car it vibrates the car. ive checked the tires and they are all at 35 psi ( i have the new lexus rims and i thik they are a diffrent psi than regular and their like wide tread). any ideas?
