you can get whatever you like/want... you will have a little power increace with just the exhaust... and no, the comptech exhaust is not loud... its made with daily driven cars in mind. The comptech headers will add about 30 hp... probably one of the most worth-while mods to the motor. I believe comptechs website gives actual dyno graphs for their different parts.
A comptech icebox is quiet... you wont gain much in the way of sound... and only a few HP, as its basically just a more free flowing version of a stock airbox. I'd suggest either an AEM or Ingen intake for your car, to get a good intake sound and the best performance gain.
My friend has a 00 Accord V6 coupe with the comptech exhaust on it and an AEM CAI... that car sounds like a V8 mustang from a slight distance! but not too loud either, just a very nice deep tone.