Ok well ive sat down and done some good calcs.
T28 is going to be an ideal turbo for me and the street.
Going by my calcs, im going to need 10psi @ 8000rpm to achieve 250HP.
To achieve 300hp i will need 18psi @ 8000rpm to achieve 300HP.(Realistically i cant see the turbo surviving on that)
These are based off 95% VE and A/F of 12.5.
If i went T25, i would be pushing its effiecny rating to far, it would make similar power, but at around 6300RPM, and peak boost would be guessed at around 4,000RPM which is where the 16VE might not handle the cylinder pressure too well.
The compressor map i based my calcs off is for a GT28R - s15/gtir t28 turbos.