Improperly calibrated injector parameters? That is a pretty elegant way to put it :] If we are talking about stock ECU cars, no nissan ecu has been completely reverse engineered to the best of my knowledge, so I highly doubt all of the fuel routines have been calibrated correctly. The larger u drift from stock injectors, the more these issues become apparent. And short of using an injector flow x duration look up table, the curve is going to be different than stock. Sure you can get it somewhat close with tuning, but its all black magic because the people who are tuning cars, are not using the right equipment, and typically dont know enough about engine dynamics to properly tune a car. Their idea of tuning, is getting a certain a/f ratio on a dyno @ WOT. That is why there are so many shitty running cars driving around.

but all of this is irrelevant, you cant deny that 550's are more desireable from a tuning and streetability standpoint. Nothing about waldo's setup says he will be making more than 350whp from what i have seen. Plus if he does go for serious power later, injectors are easy to swap. There is a reason OEM's more often than not, put in JUST enough injector to support max power.