Not a whole lot. I'm pushing 30 psi now, but more boost doesn't necessarily mean more power. More accurately, I've regained the loss of power from the turbo surge and the lag. It does spool up much quicker though. The new ported housing Has a 4 inch inlet, so it's all 4 inch from the CAI to the tail pipe, no 3 inch bottle necks. It def moves a lot more air. Sent from My Porcelain Throne using Tapatalk