Something to think about: The 2.5 has to have the right amount of backpressure to perform properly. If you get a big bore, free flowing exhaust, you will lose power. You can get a nice Flowmaster or Magnaflow exhaust for it, but I also recommend a good air intake upgrade as well. The air intake upgrade will also add some sound for you!
Yeah, you could get a Cherry Bomb but make sure it's what you need...