if i was you mate, id be looking at a silvia. First of all, if your looking later down the track and placing a turbo engine into the car you buy, there are a million and one choices for engines in a silvia. I own an r34 GTT and at your age you will quickly realise parts for them arnt as easy to come by if you happen to wreck a panel. Your still looking at around 13,000 for a low kilometer good condition NA 34, and turning the car into a GTR look alike will cost you a fortune, money that could be saved and spent on putting that engine you want into the car.
Engine transplants that have been done on silvias:
1jz
2jz
rb20
rb25
rb26
1uzfe
vg30det
and the list goes on.
And why do you want an rb26? As bad as im going to get flamed for saying this, at a younger age you will quickly find out there are tougher/cheaper and stronger standard engines out there than an rb26. And for someone thats interested in drifting you yourself would know that there are many people out there running sr20's in there skylines for drifting.
If I was in your position, id be buying an s14/s13 even a cefiro, getting all your suspension and handling/wheels etc type mods done while your on your l's and p's. Then when your on your opens if u want to do an engine transplant look at putting a 2j under the hood.
Anyways thats just my 2cents.