robs400

I have a pretty much stock 04 GT mustang other than the offroad x pipe and cat back system. I took it to the track the other day and it was hot out and the car was hooking up better than usual on stock radials. my 60 ft time was 2.05 and I could leave at around 4000 grand without much wheel spin. After I parked the car for the day I noticed that the paint now has waves behind the rear passenger windows, particularly behind the rear windows between the roof and the fender. Has anyone else had this happen? I was planning on putting in sub frame connectors and a strut tower brace to help stiffen the car up, but I had no idea that I would need it this soon.