btw, the track that I race on is only 40' by 80' with 5 hairpins. The last time I tried one way, it wasn't too bad, but I had to let off the throttle early at the end of the 80' straight. On average, the back end would jump around about twice in a 5 min race, which completely killed the race. So, I figure that I better stay with front diff. Thank's for the input, everyone.