I have had a high speed vibration for quite some time now and I would like to solve the problem. The vibration starts at around 115-120mph, and it starts almost instantly. There is no problems up until this point then suddenly it sounds like the rear of the car is coming apart. It not only vibrates, it rattles also. I first noticed it after my gear swap, but I had never brought the car to those speeds before then so I don't know if that is the cause or not. It was never a concern before because I rarely reached those speeds, but now I am trapping 114-115mph so as soon as I cross the traps the car is vibrating. Anybody have any ideas???