^^^^^ Sorry to say bro, But here is what you need to look at when selecting Injector sizes, As I am a builder and a EFI tuner and have been so for over 5yrs,

80% is were you would want to limit your injector duty cycle, not 100%. Over working an injector will cause overheating issues(the injector) as well as poor spray patterns, with spray patterns bieng VERY important when trying to burn that fuel and in a manner that makes more power for you. I always tell customers to buy and injector that leaves you room to grow, now yes in a situation were you never plan on making more than 400WHP, 1000CC injectors is a bit much and not needed, but in this situation 440-525's are no were near a OVERKILL like stated. The only time larger injectors will cause issues with a tune if they are to big, is down low(idle) due to the lag they carry while running a honda resistor box, now this can even be fixed with the new injector drivers out(FJO Ect Ect). With the correct tuning and hell even a good FPR, injectors are the last thing that would create a low power output unless the injector is not closing all the way or leaking, but this would be seen in the A/F if it was the case.

Bottom line, over working an injector is a BAD thing. The lower duty cycle you attain the better(to a point) with a lower duty rate you increase the way the injector works and sprays, an injector working at 60% in most cases will peoform better than and injector working at 75% its just how it works