-Don't need upper IC piping.
-Don't need head studs - optional at this point
-Don't need a BOV - although an MR unit is generally considered as 'better'
-Don't need boost controllers and other gadgets - just a proper tune with a capable device
-Don't need an IC
-Don't need (or possibly even want) an aftermarket intake.

The fact of the matter is that you don't need any of these items to reach the limits of the factory turbo.

 

for me:
arp head studs, metal hg, adj cam gears, 272/272, mbc, upper ic pipe, exhaust, intake, injectors, pump, and one hell of a flash. tuned on 110 and got 351whp and 375tq

 

i have an intake, bc, e-manage, full exhaust, injectors, fuel pump, and cams

I have over 350 whp now but i still have stock intercooler piping, intercooler, intake and exhaust manifolds, headstuds, headgasket, clutch, and the turbo hasnt been touched
Even all of that you dont need, but this is a pretty safe setup
You can get 350 whp with stock injectors but wouldnt recommend it

 

FWIW, the mods I listed are good for 350whp on pump fuel.