CAI/tune, Full length exhaust, gears/LSD. Those are the basics. They will help the car perform much better than stock and sound much better than stock. The CAI/tune/Exhaust is good for 15-25hp on the newer V6's. They respond very nicely to mods. The gears/LSD will help to get you into your power range faster. After that you can look into UDP's and maybe some drivetrain mods or suspension mods.