its amazing that so many of you know so little about cars

The S15 is the most "practical" of the JDM cars you're looking at, but as the owner of a JDM (for all you corn fed white guyz out there, that means "japanese domestic market", like "never came to the US, ever", and also means right-hand drive) S13, it's a pain in the *** to own. SR20s are getting more popular, but if you dont have shops local to you, you're gonna see some serious downtime waiting for parts. Also, good luck getting an S15 to you (in good shape) and registered for $25k. It can be done, but I've seen rich guys here in socal (the CENTER of JDM importing) give up because it gets too expensive, too fast.
I don't know who you think you know that can get you a R33 or R34 for $25k... definitely an R32, but R33's all go for more, and R34s are at least double R33's cost. That being said, having driven a JDM RHD R33 here in socal, I can say that it is absolute *pimpness* to drive a Skyline in the states... problems are the same as the S15 (registration, parts, etc), but more-so, since they're even rarer.
Oh, and the RB25DET powered RWD skylines were called GTS-T's, not GT-T's.
The lesson here, take it or leave it: If this is your daily driver, don't go JDM. If it's a project or 2nd car, do it, but know that it will get stolen/impounded/crashed before you want to see it go... thats just what happens to 'em here ~