I have 1 sa12 running off a db a7 2000.1, im looking for louder, because of what I need to carry in my hatch, I can only go with a single 12" the box I built is 2.0 ft^3, ported, tuned to 35htz. is it worth it to upgrade to a dc lvl 4, or z12 v.3? I don't want to have to buy another amp, or go...