Right now i running my exhaust straight downpipe. I just got back from the track and i got a 15.1. I have an aftermarket header, intake, clutch, and drag radials. to me 15.1 doesn't sound right at all. I was wondering if putting a hi-flow cat on would help at all...Also what launching rpm would you recommend?

 

Yes it will help being your stock cat is a bottleneck to your exhaust system. As for launching, try out a few different rpm ranges and see which works out best for you in terms of keeping wheel spin\bounce to a minimum