My car had a very similar issue. Turned out the upper control arm bushings at the top were toast, causing my alignment to be way off. Odds are those could be bad on yours too. Take the rear wheels off and look at the bushings. You should be able to tell if they are bad. On mine the rubber was almost completely gone and the bolts were just hanging in there.

I CONTRIBUTED TO THE WIKI!
ah... turbo. I love the turbo, the boost, the speed, the sound.
and its all better when you do it yourself. cheaper too.