Go Kart Champion
The coupe sounds amazing stock. The sedan, not so much. They tame it down a lot. Get high flow cats and Ark exhaust, that thing sounds sick. Don't expect to get any more power out of the car though. Coils + Wheels + other costmetic mods. That's all you need.
There actually is a decent tune for the G's. UPREV is the company. Wont give as big of a gain compared to the 2.0t....but they claim something like 25hp?? Add dual intakes, high flow cats or test pipes, and exhaust and you can actually bump up the power a bit on the G's. Just from what I have read