Has this problem presented itself after the vehicle was lowered,if so,check the obvious,loose suspension compoment,worn steering dampner. Anytime you lower a suspension you effect quite a few alignment angles,camber,toe,and tire scrub radius when putting wheels on with a different offset,not to mention the driveline angles.

I will assume the car was alignes after the suspension was lowered,and toe brought to close to spec as possible,along with camber.If the the vibration is felt in the seat of the car and resonates throughout the vehicle i would suspect a driveline angle needs to be adjusted,or mount is worn out.The drive line angles need to cancell each other out so you dont get any vibration,(ex.frt,flex disc will say is +3degrees,the rear pinion angle should be -3degrees,this will cancel out the vibrations of the driveshaft)Also call the mfg where you got the lowering kit to see if they have alignment specs that match your new ride height for the car.



mike(mk153)