i just have a bad personal experience with those things and i wouldnt recommend anything over 8psi on those things. they also put a lot of stress on your fuel pump. figure a 10:1 calibration on the fmu with a base fuel pressure setting of 40psi. that leaves u at 120psi of fuel pressure(thats if the thing even works to begin with), most fuel pumps wont go beyond 125psi either. id rather use a chipped ecu uberdata if i had to