Some fun figures:
ND injectors 16600-54C02, stock GT-R + GTi-R
Flow rate / rail pressure / injector time
440cc / 2.55 bar
485cc / 3.05 bar
525cc / 3.55 bar
Can estimate they flow 562cc @ 4.05 bar fuel pressure, although this was not valided in tests.
So, assuming 3.55 bar fuel pressure, 95% peak duty, would flow 498cc per injector. With a BSFC of 0.6 (a bit rich) then the injectors would flow enough for approximately 490 horsepower/ 365kw at the flywheel.
Hypothetically if it was bumped up to 4.05 bar fuel pressure it could flow enough fuel for around 525 flywheel horsepower with 0.6BSFC, leaning it out could get you 630 flywheel horsepower.
This is assuming the fuel pump is up to the task and can flow enough lbs/min at the absolute rail pressure (base pressure + turbo boost).