Is a stock GTR better than a stock GTST/GTT.......Yes. Depends how u look at it..
Can a GTST/GTT be modified to smash a GTR........Yes.
Can it be modifed easily to smash a gtr....... No.
Can a GTR be modified to smash a modified GTST/GTT......Yes.
Does it even need to be modified to smash a gtst/gtt......... NO
changing turbos n make more power doesnt mean ull beat a gtr... u need a fairly modified gtst to beat a relatively stock gtr... ur talkin turbo, suspension, tyres, ecu, injectors, fuel pumps, clutches etc