Definitely don't want that turbo. For a GT, I don't know if I want a turbo at all. I chose GT over GTS because of gas mileage and insurance (daily commuter to college). A couple years from now, I'm actually getting another car. Either a GTS, 350Z, or I might even look at the new Eclipse if it impresses me, which for some reason doesn't seem likely.
If anything... I think I would go supercharger. Least expensive, and it would make the car somewhat of a sleeper. Given convenient circumstances.