Dont confuse more PSI as more air. You can have same weight flow of air (lbs/min) at different pressures. Cylinder pressure is what destroys head gaskets and thats based on how much air flow you have going in, how much fuel you combust which produces power. Could be 18psi to make 500hp or it could be 5psi, but it will take about 50-51 lbs/min of air weight flow to make that 500hp. Turbo size will have influence on the efficiency of the compressor, thus the temperature of the discharge compressed air changes. So you may see different volume flows of gas and thus different psi levels to produce same weight flow