I have a Superchip and I'll tell you this...without it, I do NOT like driving my car! Thats what it does. With having an ATX it completely changes shift points and you get quite a bit more HP. Im not going to quote numbers but its a good gain but I thought I remembered reading it say about 10-15% gain. About the High octane gas...I recommend following the instructions and getting it...I'M not going to risk finding out what happens if you don't use it. I feel that it has probably been the best mod that I have done to my car yet.
