Same issue here on my stock setup - had the wheels/tires road force balanced and still get the slight vibration over 75 or so. I was thinking along the same lines as you - my PS2s have seem some abuse on the track. At this point, I'm going to ignore the issue until I put new tires on and see if it goes away then.
This car seems especially sensitive to wheel/tire imbalances...
Originally Posted by persian54
I have a slight shimmy/vibration over 81mph on mine...I had it road force balanced using a Hunter GSP 9700, twice!
I'm thinking it may be the tires cause they are pretty beat up from track use..but it's still a PITA.
Wonder what I can do??