All the vibration is gone!!! It was the driveshaft. Runs smooth as can be now. The QA1 was missing installation hardware. And the customer service over there did not help me out. Maybe because they do not make it anymore? I had a brand-new aluminum, latest version, DSS, sitting in my garage with hardware. They installed that and it did the trick. Now I have a very low 9 second or high 8s car depending on elevation that drives like a dream.