Well with the hahn stage 2 set up, 415cc injectors, fmu and s-afc hack i had 220whp and like 195 ft lbs of torque at 15 psi. I wouldn't take it over the stage one set up specs with out an intercooler. My car ran horrible rich all the time never could get the fuel curve right. My Buddy's v8 supercharged ford 150 saw better gas mileage than my set up. i fouled plugs and o2 sensors traveling to the va beach from Hampton . Using larger injectors as primary in our motor is pretty much not an option the ecu wigs out and tries to compensate it. there's no true piggyback set up that works and allows the car to run above 10psi. the 8 injector set up hahn has is the best because it allows you to run stock fuel curves every day driving, then opens the second set of injectors under boost setting only, completely keeping the reliability and gas mileage. By using the 8 injectors you only have to tune wide open throttle settings under boost where 4 injectors and piggy back fmu/fuel management you have to tune closed loop and open looped settings. If i were you i would build the motor break in the motor with 5 psi, save for the front mount and 8 injector set up and up it to 15 psi.