Re: reverse mount subs
Ok first the correct term is invert, but you have about everything else right. You need to reverse the wiring on each sub. (+ to -) As far as airspace, you will just have all the space that the box says it has because the basket will be on the outside. If you want to figure it out, its LXWXH (Compensate for wood thickness) and divide by 1728. You don't need to separate the chambers, though it isn't always a bad idea.
Alpine CDA-7995, A/D/S 3 Series Comps, ED 8A, SoundStream Reference 604, 98 Civic Sedan