U can hit 300hp if its a lower reading dyno. The number doesn't matter, the increase does. Find out what his dyno reads first and you should be around a 70hp increase over stock. Up grading the fuel system won't help because there are other things that need addressed first. The whole intake system needs redone. Intake, tmic, tgvs etc. also the exhaust sucks, header, ewg etc will really open it up and take the stress off your fuel system. I was running stock injectors to 330hp and 360tq on a dynojet that read around 230hp 240tq stock. That equals 21psi down low to make the tq and 15.5psi to make the hp up top and I only got to 94% duty cycle which is low by some tuners standards. There are a million ways to make power on these cars! Sadly part by part only adds a few small ponies here and there. Only way to make bigger, cheaper power is E85 or a bigger turbo.
Scott-2011 WRX 335HP 394TQ 93 VF52!