I'd say two ppl experiment with this stuff. Both cars with same Intake exuast headers/ blah blah.. then the Turbo. and just race.. of course distance of the race is a big factor. i would think Gts will kill in the long run and gt wil kill ona shorter run..
Well, the only way distance would make a big difference is that the GT and the GTS are operating under different final drives.
If the GT has a lower final drive than the GTS. The GT will overtake in the end. Vica versa.
If you were to drag race, the car with the higher final drive will definitely get to 1/4 mile mark before the other. (Then again, transmission depends solely on how much power the motors putting out.)
Only problem with comparing the GT and the GTS is that the GT has lower compression, and can boost higher. Are you talking about keeping the block stock, where the GT has 10:1 compression and the GTS has 11.5:1 compression? If that's the case, the GTS won't be able to boost high.. maybe 5 - 9 psi. The GT could possibly boost from 9 - 15 psi.