go get a box made. It will be cheaper and built tougher. Not only that but tuned to what YOU want and the subs you will have.

Ported can sound just as good as sealed depending on the tune,music,car etc. Ported boxes are louder and more efficient...as stated before. Efficient becuase it takes less power to get more bass, However,expect your subs to suck more power out of your amp in a ported enclosure if you plan on cranking up the volume.

Prefabbed boxes suck. Not all, but majority of them. Nothings better than getting one built for cheaper. Its louder and your helping our your local business.