Not sure where you saw these maps, but I've yet to see a b16 make that kind of power with that turbo. The most i've seen was about 220whp @ about 12psi. Then again it's been a while since I've run that turbo so things could have changed since then....

Those maps that you speak of, are they in reference to the b16a or another motor? Each motor is going to flow differently.

Just out of curiosity how come you are running that turbo? The only reason why I ask is because when I swapped to my current turbo it made such a big difference (on the same tune and boost level) that I wished that I had switched sooner.