Don't waste money on a Thermal exhaust for the Celica. A friend of mine had that exhaust on his GTS and it's by far the worst looking and sounding exhaust I've seen/heard yet for this car. It's loud, raunchy, and just looks like crap.
Thermal makes pretty good stuff for Hondas (have a few friends that run them, pretty good stuff), but they flopped on this one. Yech.