[qwikz28]

I'm going to have to mirror Scott on this one, and emphasize alignment. My alignment was fresh from the now defunct TTP, but my car felt sloppy. I blamed it on old bushings. I finally manned up, and went to an alignment shop in Central Jersey, and man was I shocked at the results. He didn't really add any more camber, but he corrected the caster and toe which were apparently the source of my instability.

Weird things were corrected in the process. My car is now super stable at high speeds, the 80mph shake is gone, and my car now prints money. Whether or not that is what is wrong with your car, I don't know, but perhaps looking into your alignment specs could save you a ton of money in a new rack and other stuff.