As above... all I know I would never go for over 380 PS without 6speed or PPG conversion.. My 5speed Type-R gearbox gave up last year at only 330BHP...
I'd get the smallest GT30 you can get to maximise quick spool up, I think it would suit the short gearing best!
MD321H (like JP's) is still good for 420-430bhp! That would be my choice for a type R
Dan
md321h like than said or the andy forest td05 20g would be what id go for and id defo go for the 740cc injectors with your build. im sure ali will steer you in the right direction about which turbo to fit the build perfectly