Originally Posted by 2fast4you

THANKS

The theory goes like this - The OEM fuel return valve opens at 130 bar and allows pressure to drop to 127 bar,then it starts building pressure back up again until it reaches 130 bar at which point the cycle is repeated. The RS4 valve does not open until the pressure reaches 136 bar and allows the pressure to drop until it reaches 130 bar before it starts building the pressure back up. So a stage 2+ map requests 130 bar of rail pressure therefore this mod should be beneficial, as it will help maintain 130 bar fuel rail pressure rather than fluctuate from 130 - 127 bar with the OEM system.
About the cam follower for the HPFP I juts saw that I really don't know