As others have said, the exhaust is not going to give you major power increases due to the engine.

The exhaust that is being sold sounds like a catback from the description (so would be the b-pipe, resonator, muffler and tip).

If you are simply after a sound difference (and want the muffler tip to look a little different) just stick with a muffler, as it will save you a whole heap. If you have the cash and dont mind doing it, then upgrade the whole system. If you going to the effort of getting headers and a catback system then personally I would upgrade your cat at the same time.