Mine did the same thing but I actually just had low front tires. Mine were running around 20psi and the rated psi on the tire was about 35psi. It didnt look low but it was definatly low. Its worth a looking at just in case .
__________________ --Kenny-- Myspace Speed costs money, I work with what I got
you may have bad tires, low pressure, or off alignment, or bent rims. I recommend a check for all of these, especially if it shakes at around 50 mph. Gl update when u find out
I would suggest finding an installer local to you that has the Hunter Road Force Balance machine and having them check your wheels. It seems like standard wheel balancing just doesn't cut it on these cars. Every time I've had a regular balance done I've had to go back and get the road force to fix it. They should also be able to see if there are any obvious problems with the wheels themselves.