Does your post say you have 22" wheels? If so, you probably have a lip in which case water is getting caught in the rim and throwing the balance off causing the vibration/shaking. It happens to me with my 996tt, happened on my S4 and I have read many many posts of it happening to aftermarket rims with lips. It is like having snow stuck in the rim and it vibrates/shakes like hell. The price you pay to pimp!!
