In my opinion, the best upgrade for your base, assuming you don't track the car, is an LSD. That will help you put the power down, and you can go to 4.08 or 3.9 gears at the same time, which will increase mechanical advantage. If you're planning to track the car soon, then an oil cooler.

Totally not what your looking for but don't forget brakes. More power = more stopping power needed.

I had an '09 base....installed stoptech rotors and pads...well worth it.