I was wondering if anybody know how to get more fuel delivery to my engine without bigger injectors, or software tunning (im running nos). Maybe a after market fuel pressure regualtor? Does anybody have one, and how beneficial was the upgrade? Any comments on this would be very helpfull. Oh yeah, does anybody know why my car's exhaust pops when i start up my car and rev it up (cold start)? It pops when the rpm's are dropping. Im running headers without cats. It only happens when my engine is cold. My car also runs better when the engine is cold.