Thanks guys, its nice to know I had the right idea.
Stu, 6 more db for a 2nd sub? That is impressive. Its odd, I'm more knowledgable about Car Audio, and there, it seems 3db is like doubling your power. Recently I've been reading into Home Theatre, and just like you say, 6db seems to be doubling your output. Gonna have to look into that. Thanks for your info on your experience with the PW-2200.
Ear, thanks also, your knowledge/experience with subwoofers scares me From what little I've heard from/about you, you have one heck of a collection.