Hi, I registered just to reply to this post
Ive had my gtir for a few months now and ive yet to lose to a Gtst. I put quite a few car lengths on my mates series 2 r33 gtst (with blitz exhaust+air filter) pretty easily.
My car is bog standard except for exhaust (hyper medallion or something?) airfilter and a daiken heavy duty clutch
Stock for stock off the lights the gtst has NO chance but rolling start might be a different story (ie. i havent tried)