huh, it looks like the12volt.com is down at the moment.. but the link that durwood provided to the home theater site provides a lot of good info about it.
being that you want to use your existing box, you will need to use the volume measurements, and plug them into a box modeling program to see how all the shallow subs react using that box.
honestly, me, or durwood are bad people to talk to about 'getting a bumpin system.' both of our installs focus more on sound quality then on disturbing the neighbors. though either does a ok job of it when required ..
and i don't think you have been officially warned-- this forum is mostly for installing computers in cars, and as such, there isn't many resources, or members here that are
have a lot to do with audio systems. there are a good handful of people(durwood, myself, gizmo, and philg are about 'it' these days), but a car audio specific forum is definitely going to have more info. check the sticky at the top of this car audio section for a couple of sites..