While im all up for modding cars to owners tastes, before you go down this path, you may want to consider the future.
Eg, you'll spend multiple $1000's on this before its done. In the end it will still not be a GTR. Then convert the motor to a 26, that doesnt make it a GTR either. Put a front diff in and AWD? Nope, still not a GTR.
What im getting at, is that if a buyer comes along and does a VIN check it will show as a GTT for ever. Also im sure if you add up every cost (i mean, every single cost/part) needed to do this, you couldve bought the real thing for similar money as the exchange rate vs cost of GTR's in Japan isnt all that bad right now.
Lets say you ignore me and go ahead with it, in 5 years time its still not a GTR, however you've spent so much money that you're too far in debt to the car to sell it and get the real thing as you'll NEVER get the money back you spend on it. Spending 20k for example on a GTT will increase its resale value by a bit, but spending 20k on a GTR will increase its resale value slightly more as they will always be the more desired versions or the R34. As an example, have a look at the R33 market currently.
Best of luck with it all