I've noticed that my 6 rides pretty rough. It's really bumpy, it follows the grooves in the roads and it pulls to one side when I brake. I drove a friend's GT and the ride was much smoother, and none of the other problems I listed affected it. I'm pretty sure the following the road/pulling to one side when braking is an entirely different problem, but why was the gt so much smoother?

 

worn out shocks and struts will do that also is your car lowered any? if so that will make that happen also

and as for the tracking it could be your tierod ends and getting worn out allowing extra movement