Headgaskets and Aplications

Alright, im in the process of building my sr and have been doing my research and have come up with too many answers to my question about headgaskets -

My main problem / concern is - Im looking for the power to be in the range of 380 to 400 with this set up -

From top to bottom -

BC 264 or 272 cams -still up in the air right now ( opinions and comments feel free )
BC Titanium Springs & Retainers
BC SS Valves
HKS Rocker Arm Stoppers
Apexi 1.1 mill Head Gasket ( Purchased already but i still dont know if this is the best one )
Weisco Pistons .20 over
Eagle H Beam Rods & ARP Rod Bolts
ARP Main Studs
ARP Head Studs
Greddy Oil Pan
Custom Race Bearings
740cc Injectors ( dont know who to go with and if that is the best size )
Power FC D Jet

Turbo Set up will be Either gt2871r with megan manifold for now since im broke

OR

gt3071r because i dont know if a 2871 can get me to 400hp safely -

Now my real QUESTION IS ----------

If i am going to be upgrading turbo next year if i find i want to make somewhere in the range of 400 to 450 hp, which head gasket/injectors/turbo and cams would best suit my application -

DRIFT SPECIFIC CAR - no drag racing - no circuit and not a daily drivin car -

realistically money wise i think the most power i will get right now is 350 to 380 with a 2871r

that way i can still keep stock manifold if i want, stock taka lines, and no custom exhaust for the downpipe -

gt3071r i would be needing a waste gate/top mount manifold/ and custom exhaust - so basically

WHAT IS THE BEST COMBO OF PARTS FOR LOW END POWER WITH MID RANGE AND CAMS THAT WONT LET THE POWER FALL OFF AT HIGH RPMS -

any comments and opinions are wanted thanks guys

is a 2871r just NOT ENOUGH?

is a 3071r too laggy even with the .64 exhaust housing ?

is a 740cc injector sufficiant for 450hp ?

is a smaller thickness head gasket going to give me to high compression that i will run a risk ? .90 vs 1.1 vs bigger ?

etc all these into consideration - im looking for the all motor feel in a turbo car with mid range and smooth power -

twinscroll 3071, 850cc, stock thickness hg w/ ARP studs

/thread

thats what i want haha, but its a little pricey right now, you think the smaller exhaust housing wont be laggy ? ive never drivin a car with gt30 and supporting mods, but i think to reach my hp goal gt 30 is my only option -