GTI 1.8T Automatic

I'm concidering to buy GTI 1.8T with shiftronic transmission, but first can anyone tell me if I can upgrade the turbocharge to Stage III if the car is not manual transimission? And how will the shiftronic impact my supping up of the car?

even if the car is tiptronic it shouldnt make a difference. the stage 3 turbo will still work. about the other mods it depends on what u want to do. u wont be able to do any mods involving the shifter( u cant get a short shifter).

Im new to the import world.... what is the difference between high-end and low-end cars?