nothing, there is a thread floating around the forum of a guy who had a TRD exhaust and a short ram intake with a pedal commander throttle controller and put it on a DYNO and got little to absolutely no power gain....and running the quarter mile on a track as well yielded no noticeable performance results...to get gains you need to tune your car after installing bolt ons, and nobody is tuning a corolla, trust me..with that all said you can CREATE the feeling of performance...the short ram does make a cool noise, and an exhaust is always fun... a pedal commander makes your throttle response better but doesn't make your car faster...its similar to the Sport button on the corolla S but on steroids. with all that said i do have a short ram intake, not for performance, but because i like the intake sound, and i got a steal on a exhaust so i got that on mine too...