Okay I know it regulates the fuel pressure, but how exactly does that benefit me? I have to get my car re-tuned since I installed a 255 lph fuel pump, would a FPR be of any worth to me to install prior to having her re-tuned? BTW the car was getting no fuel above 4500 RPM after the headswap that's why I went with a new fuel pump and am trying to find out how to get more fuel in there.