Sr20KoukiS14

I have an s13 sr20det with the j4 ecu with a stock tune. It has a 300zx maf, its been bored .20 over, stock 370 injectors(which i have read that they are more comparable to a 400cc size and that the tt 300zx injectors are actually smaller because of the way the flow), walbro fuel pump, aeromotive fpr, stock manifolds, fmic, an innovate RC-1 wideband, and stock t25. What I want to know is, can I tune my engine by raising the fuel pressure manually at the fpr. I know that a higher fuel pressure can sometimes hurt stock injectors, but i just want to tune with out touching the ecu. Old school tuning more or less. How much boost can I run with this kind of setup???