Full Tune
 

how much would it be to fully tune out a R34 and what kind of horespower would i get out of it in the end?

you're asking a very broad and vague question.

as a newbie you ought to research the topic a bit more. you must not have any idea about tuning and what it entails or what shape it could take. you can tune a car for myriad goals:

torque
horsepower
grip driving
drifting
drag
lots of low end
lots of high end
lots of mid
any combination thereof

and expect to put any money you ever make into the car. i'm assuming you are a teenager/child based upon your info and manner of questioning.

So what if i asked what should i improve to get better results in 1. Response 2. Overall horsepower 3. Acceleration?

again this is a large universe you are asking about. opinions will vary according to personal taste and experience.

i will lump response and acceleration together as those are virtually the same. i will avoid saying "well, you can have anything you want if you have the money." that is a foregone conclusion.

but what do you really mean? do you have any money? if not, you cannot do much of anything. i can tell you the cheap way or the right way. which way do you want? the cheap way will not garner much performance. you will be limited to bolt-ons like CAIs and UDPs.

the first order is to get the GT-R to breathe better. this includes a lot: uprate and/or port out the turbos, port-match the intake plenum with the head [that will be ported], uprate the cam to more aggressive duration and lift [whilst changing the entire valvetrain and it's parts], uprate the FMIC to higher capacity, swap the downpipe for larger diameter, ditto for all turbo and FMIC plumbing. this will cost in the thousands but will garner both large horsepower gains simultaneously with superior response.

i recommend an SAFC2 (fuel converter computer mounted in the cockpit that you can dial) to bypass the ECU's stock fuel mappings. once you breathe better you will need to uprate the FPR (fuel pressure regulator) and fuel pump. you may want to port the throttle body as well, and uprate the MAFs (mass air flow meters). the OEM standard RB26 air flow meters and injecotrs are good for up to about 440ps; when using over 1.2 bar (about 16psi) boost pressure, head gasket should be changed to metal.

all of this entails weeks, perhaps months, of work and thousands of dollars in time and labour investments. if you want to break 500ps you will need to change the turbos entirely, for example to HKS2530s, and go with a standalone ignition system as well as do everything suggested above. you will need to get an oil cooler as well to handle the extra stresses of the higher heatings. i'd recommend, too, going dry sump to avert viscosity/resistance at the crank. beyond 500-550ps, you're getting into enormous requirements to take it higher in hp, more for drag.

upon any upgrades, you must consider, too, the brakes and suspension requirements as well as the clutch to put this power down. those are in and of themselves multi-thousand dollar swaps. you can easily sink $10 grand into the GTR to get it to 500-550hp with all i have stated.

and i never mentioned catback systems [exhaust and muffler upgrades]. a good system will be at least a thousand dollars. just for pipes and a muffler.

Are the HKS T51R SPL Turbo's a good choice for the R34?

and i guess i should mention that i am wanting to make it a GT racer not Drag or Drift.

and money isn't an issue for me. if i cant afford the parts i need ill wait till i can. because i would rather do it the right way and get the most performance i can and not the cheap way and sacrifice the quality of the tune ups

i have no experience with those. but i can nearly guarantee you off the top of my head a T51 sounds way large in trim for GT racing. that seems more of a drag application. whenever you see numbers like "T51" or "60" you're waving practical driving bye bye.

for GT racing i'd consider HKS 2530 or GT40R as the largest, depending on myriad other variables in your tuning approach.

alright thanks for the info