Ive been running a ct kit with a t66 for a year now without any promblems on a stock trans, car only runs 10 degrees of timing sometimes less but still made 250s whp. during the winter i was pushing 11psi with more timing, it was proly 260 270 whp then. trans has 133k on it 27k of that has been lots of abuse. turbo was put on around 125-127k mark. tranny does show signs of wear but still runs fine. (bangs into gear sometimes small stuff. shifts fine).