That space looked like a good option if you were going to build one enclosure to the left rear (right requires you to relocate the pump for the door locks ect.). You could use some of the wheel well too you could gain some additional airspace so if you are using Kappa Perfect and not Perfect VQ then you will want 1-1.25 cft per woofer for a 12' .75 for a 10" lining every wall of the enclosure (except the woofer mounting area) with about 1" of poly fill or fiberglass insulation Power it with about 500 watts RMS from a good CEA 2006 rated amplifier and you should get some good output.