On the wife's tc we wanted to do a clean mod track and do it slowly as she learns the different types of mod stuff out there. this is her first car to mod and it is upto her, but I have done a few and am guiding her.
The first thing we did was install a Short Shift kit to improve the shifting of the car (does not add power, but quickens shift). The next thing we did was add some personal touches. We installed a full third brake light to make it look cool in the tail. The latest was a Cold Air Intake.
Thread that shows install:CAI on tc
do a search and you can find some cool things.