have a flick through Rb25 Turbo Upgrade, All Dyno Results might give u a better idea different results people are getting with different turbos.
i run a garret t3076r which is a lowmount with internal wastegate.
i find it to be pretty responsive however other bits n pieces will need upgrading to make the most of it. (am aiming at 1.4 bar)
if you only plan to run 1bar however you may get away without some of that.
i'd have a chat to some workshops and get their opinions then do some research based from their recomendations.
ultimately the more honest you are with what u want from it in the first place the less dissapointed you will be in the long run.
good luck with it.