I'm not sure if GTST / GT-T's would comply as I don't know the production figures of them.
Anyway, you can't sell the car for four years so if you get bored with the GTST / GT-T and you want a GTR, then bad luck.
You can register a 1989 BNR32 under a classics car law which means that it doesn't have to meet frontal impact and emission standards. 1990 and over will have to meet emissions so the only way to import 1990 and above GTR's, is with a SIV permit.