The 8.5T isn't going to break anything. People are running 5.5T & 6.5T in AE T4's and Losi XXX-T's. I would go for the 60A version for any offroad car bigger than a 1:10 buggy. As for your TT-01 & TT-05 you'll be fine with the 30A and "380" sized motors (9T and up).

Jay