Right now, my set up is just right. Spool up is instantaneous with E85, 9.0:1 forged pistons, Killer B 2 bolt + Perrin Performance Big Tube uppipe. Slight lag with 91. I'm glad I went with the Tomei M8265. If I were to do it again, I would have gone straight to the Killer B with the v banded up pipe. This header goes well with the spool characteristics of the M8265. Very strong midrange and top end power.