I just wanted to advise everyone.
The FFR PDG GTM team just finished some testing and one of the things we were focused upon was alignment of the rear end.
We took the rear toe down to 1/16 total toe in...and I just about wrecked the car!
The car was VERY scary with this little of toe in in the rear. Every time I would simply lift the throttle to do even an upshift, the car would throw the back end out to the left. So much that even at 100+ going down the straight I would have to correct with the steering wheel when lifting for upshifts. It was also just, generally, very unstable at the higher speeds.
I can tell you that many of the issues that have been presented on this forum of "stability" can undoubtedly be traced to this question of rear toe, and how much is the correct amount. After the experiences I just had with this test session, I would not recommend anything less than 1/16 total rear toe in, and 1/8 total toe in is probably going to be where it feels the most stable without having the rear end become "tight".
We adjusted to 1/8 inch total toe in and the issues simply disappeared.
I will finish off this post by saying BE CAREFUL out there, as I can't imagine the trouble I could have gotten into had I been on cold street tires. It was scary enough as it was.