im aiming for 500+ whp street driven.
the specs are
darton sleeved (stock bore) block
je 9:1 pistons
crower rods
extrude hone + port flow head
skunk2 manifold (port match)
crower titanium valve and valve springs
type r throttle body
apexi' gtr intercooler
with a rev hard cast iron manifold
its going to be tuned with motec m4
a set of 720cc injectors
im now using a t3/t04e but want to go bigger.

 

A) how much of the list do you actually have?
B) Which stock bore?
C) if you already have the revhard manifold, its gonna need a T3 turbing housing.
D) I like a turbo with a little more lag so I get fanatical top end. Do you?

so....a .63 AR/T3 stage 3 or 5 turbine with a 60-1 compressor wheel
or stick with the T3 stage 3 or 5/.63 AR but with a T04E compressor (up to 52lb of airflow)

if you haven't got the manifold yet , get one with a T4 flange and stick with a T04E. .58 AR turbine

wait for other suggestions