Audiobahn (and almost every other company out there) spends a lot of money/time on R&D. They know what their product is designed for and how it will perform. I wouldnt venture too far from what they say. Its like telling BMW they need to put a higher gear in the rear diff. because you want to come away from the stop light faster.
Audiobahn has always been geared towards sound quanity not quality. You may be suprised what you can get outta them though. I would build the ported box and as long as its correct you should get a pretty decent sound. From there the quality will be in the quality of music you listen to. If you primarily listen to dance, rap, techno or something of that sort, the bass tracks are poorly recorded anyways and it wont matter.
A sealed box has a smoother response at a sacrifice of volume and a ported box generally will play louder at certain frequencies and less at others.
hope that helps...
-There are 10 kinds of people. Those who understand binary, and those who do not.
-If we ever forget that we are One Nation Under God, then we will be a nation gone under...Ronald Reagan