actually when i got my chip i knew i was getting nitrous, so i didnt have him advance the timing even if i did... the single ports can run a little advanced without getting detonation. SPlit ports are the ones that have more problems with that.MusclesFromBrussels said:not really worth it on a pre 99 unless ur gonna run nitrous like me. ZIMstang is gonna have to either get a flip chip reburn or take the chip out. Advanced timing plus nitrous is a no no :no: :no: I noticed a decent gain with mine on the NA side of things but wouldnt have gotten it if it wasnt a part of my nitrous project. It firms up the shifts a bit but nothing a 70 dollar shift kit cant do better. Id say save up a few more bucks and get a set of ported upper and lower. With ur gears ur low end is already decent but ur top end is what is killing u. Intakes help after 3k where ours really blow.