bp increases thermal handling. also, on the size, get what is going to fit in your car with the box that will be optimal for the subs. I'd get 10s to fit the optimal size box instead of getting 12s and only giving them a minimal sized box. However, if you can fit a box good for the 12s then go ahead and get them.

well i have a ranger ext cab. no seats in the back so theres really nothing back there. i just measured and i have about 16 or 17 inches from the back wall to my seat. depending on where u measure bcuz the higher u measure the less room bcuz my seat is leaning back. but i measured in the middle. i was wondering if that would be enough room for a nice ported box that will hold 2 12"s

you gave one dimension. how would anyone get the volume measurement when only one dimension is given?

9.-1.5 ft^3 per 10" ssd or 1.8-2.5 ft^3 per 12" ssd can be found on their website in the tech section.