well, I did 13.3 with stock IC, cat back, turbo, IC pipes, cat, etc...
All I really had was fuel (lex 550s) downpipe, cheap filter, and an avcr.
1Tuff. I BURN EM.
I run 17 psi, and let them pull through my front brakes. I hold the brakes just light enough to stay in one spot, and then...