The 26 never got variable valve timing unlike the 2jz , which makes such a big difference on the road and to general drivability, in fact the 26 had little development from '89 but the RB25 was developed right up to the end , thats why many people think the RB25 neo is the pinnacle of the RB engines , a stock RB25 neo makes more torque at a lower rpm than a stock rb26 , the saving grace of the 26 though is its potential for tuning but as Tricky Ricky says the LS motor has a huge potential for tuning since the market is many times bigger than that for the 26 and economies of scale make many of the parts surprising cheap especially if you are used to tuning Skylines.
I was planning to fit an LS engine to my 33 GTST , was considering a RB30 build as well but the LS was going to be about 30% cheaper for a 600/600 build