Well, from what I've read, porting is when you have a tube that extends into the rear of the enclosure which allows it to move air from behind the speaker, and that allows it to be a little louder, but most people are claiming that it also reduces definition. Since I'm not looking for pure volume, I thought I'd go with a seealed enclosure, but if I just put that in the trunk, then the output of the speaker will be muted by the materials that separate the trunk from the cabin. What I was suggesting is having a normal sealed enclosure, but then mount it underneath the rear deck so that it points upward through a hole I've cut in the deck itself. That would still keep the sub and the enclosure in the trunk, but it would allow unfettered sound to get into the cabin. (The reason I'm thinking about this is because I would like to get better bass response, but I hardly want to have my whole car vibrate down the road, and I'm afraid that that's what I'll end up doing unintentionally.)