i've always thought that RB26 into a 33 GTST is one of the much underated combos out there. can make an easy 260 rwkw (with stock turbos, stoc injectors, stock cams, stock GTR cooler, stock dump pipes etc). and the weight difference between a RB25T and a RB26TT is not soo much.
however in a 32 GTST I'd prefer a worked RB20 (something like Roy's). it just seems to suit the car better as they are already quite a light, small car and the 20 can still make lots of power, and pull decent revs. plus in the 32, you need to get a 25 box to go with it. the 20 box wont last behind a decent 26.
If you want RWD RB26 I say go 33 GTST, or if you really want a GTST I say stick with the RB20, or do an SR20 swap. SR20 in 32 GTST is pretty sweet.