Trust me, I have specced, paid for, and owned a 900bhp RB30 engine etc, and know what GTR bits cost.

If your paying the usual suspects I dont think for a second youd get close to a reliable 700-800bhp for 10k inc mapping, labour, all the ancilliaries. Not even if you got RIPS to supply you with the parts rather than getting ripped off in the UK.
At that power nothing standard barring inlet manifold is any good to you if you want reliability, and you may as well change that too. Nothing at all.

And then the stock box wont last long unless you driving in a way that even 400bhp is a waste, even after youve blown about twice your 10k budget getting everything ready.

Even RIPS list a "complete package" (ie turbos etc too) starting at just over 9k, then you gotta get it here from NZ, pay the taxes, buy the fuel system, the clutch, the managment, all the various ancilliaries, get it fitted, get it mapped, etc etc, and by the end of it you will be coming on for double your 10k budget.

And if you paid a UK Skyline "expert" to do the same (ie built it all) its safe to say itd be twice what RIPS will charge you, and then some.

If swapping to some direct replacment turbos on stock manifolds alone costs 2k, without the tons of supporting mods to make use of them, what you expect?

Trust me, been there, done that, know the prices even when saving cash massivley by doing stuff most people dont (ie fucking LOADS of research, buying abroad, and getting shit custom made), and its WAY more than 10k.

Seriously mate, its not as rosey as you think