You dont have to use as much power to run a single 12 as you would 2 10s of the same standard.

 

i got 2 12's under my rear seat i used a 1997 GMC box i forget the year but pretty sure 97 out of all things but you would have to cut a chuck the box but it wont open the box, dont worry. and i had to move my jack box to my tool box on my truck. it sticks out under the seat about 2" - 5" but hey it hits good still