his motor had forged internals,tomei headgasket, stock head, 750cc injectors , Power FC , thats it in a nutshell though.
a good condition Rb25 can still achieve the same numbers though, its just the amount of a beating it can take ... which is alot with stock internals with good compression.
about Turbo's from turbonetics i really dont know anything about that but if you research on how to understand Turbo A/R's then you can find just what your looking for.
go here ---->
TurboByGarrett.com - Turbo Tech101 educate yourself and you will have a much better understanding with what you want.