as some others have said above. RB25DET is better than RB26 for drift... cheap bolt on mods, enough power for drift and cheap initial purchase price compared to an RB26, which isn't gonna be that much of an improvement in drift setups... you're not building a circuit racer or drag car here. Your primary concern is to make sure the engine dosen't blow while you sit on the rev limiter all day...
Getting an AWD skyline/cef for drift is dumb, purely because the front axles add weight and reduce steering angle, which you'll need to get good lock. Again, not really building a circuit or drag car to need AWD.
If I were to build a car just for drift on a limited budget, I'd just get a regular manual Series 1 R33 GTSt. You can have one landed complied and registered for around 10k these days, you've got a standard RB25DET and if you put some bolt on induction mods, strip it, take out HICAS, change the suspension and add a mechanical LSD you're well on your way to a sweet sweet drift car for under 15k. Panels are cheap as hell and spare parts are so cheap... perfect for a drift car. Plus it's newer than a rusty old A31, S13, or R32.
f**k being different... I'm sure your bank balance dosen't care if you're the only monkey on the track with a certain type of car.