The 818 I purchased partially complete and then finished has a 2004 WRX engine with unknown modifications. I know it has a different blow off valve as it now blows off to the atmosphere whenever you let off the gas. The turbo looks newer than the engine but not sure if it is stock or not and not sure if any tune has been added. I installed a boost gauge when completing the car. The gauge peak pressure is 20 psi which the engine easily hits at about 3500 rpm. Wondering what the peak pressure should be and should I be worried? My history is more with superchargers and this pressure seems excessive, but maybe not. Just don't want to blow a head gasket or worse.