Just like a Grand National, the first thing you have to do is let air in faster. Just installing a K&N Filter was enough to wake it up a touch for me. Thats easy enough. I opted for the direct replacement because the stock air filter housing pulls cool air from the wheel wells. Some use the cone style but i don't see how pulling hot air from the engine bay helps as much. But it looks better.
Then comes a trifecta tune. You have to decide if you're going to use E85 or premium gas. The E85 may be too much for the fuel system since E85 needs much more fuel in the chamber to work effectively. The higher pressure of the tune takes the fuel system to the limit. I have seen a number of people with codes using E85 and tune. But that was before the E85 specific tune. You have to worry about warranty as well. If the dealer finds out and you blow your motor the repair comes out of your pocket. I have yet to hear of any warranty issues though.
Also like a GN, you have to let the air out faster. You'll want do a muffler delete and ZZP downpipe package. The car isn't loud at all without mufflers. Just like the GN, the turbo muffles the sound. Your turbo can use a larger exhaust as well. A GS has 3" but I believe the turbo has a smaller diameter.
With the above goodies you should go faster than a stock GS! You'll think you stuck a new engine in the car.
Bad News Racing seems to have all the goodies.
Hope that helps
