two tens ported=louder then two twelves sealed.. and tuned right, hit just as low.
they 12" m3's might fit, but i don't think so. all my dual ten boxes (3 of them) for under the back seat and my one dual 8" box were all 1/2" mdf so that i could get enogh airspace and mounting depth. 12's will be pushing it, unless u 'glass.