i will tell you this, in my roommates 08 vette we are having problems with the trans making the shifts while spraying...it's on a 2 stage 175 shot, he comes out on the 75 and hits another 100 on it...it will almost always make the shifts on the 75 alone but not on both kits together, it will bang rev limiter everytime....i have the tune set to shift at 5800rpm and the rev is 7000rpm....there is no aftermarket stuff for the 6spd trannies yet and thats the prob...a simple shift kit would fixed the shifts for sure...his trans he already broke is sitting at RPM waiting for parts to be machined...his will be the first of the built 6l60's made by RPM