ok Roy, im bored so i have collected some of the 300rwkw on 98 sheets just to satisfy you and shut you up.
a 10cm should get you there, with the right choice in cooler and hi flow cat and exhausts, there will be no restrictions provided the tune is spot on.
this was confirmed by Yavuz @ unigroup engineering who is highly regarded on this forum by sau:nsw members, he tuned many gtsts that made anywhere from 250-310rwkw, deciding factors were listed above.
1)
R33 GTS-T
TD06-20G turbo on high mount manifold
Tomei cams and cam gears
Forged pistons
650cc Injectors
Blitz external wastegate and screamer pipe
Blitz fmic.
Splitfire coils
Haltech E11v2.
On pump fuel
2)
SR20DET @ 19psi on BP98