Im looking at 12 inch subs my choices are sundown audio sa12,diamond audio d6, and ssa subs. Is there another kind I should go with? 2ohm or 4ohm? Another problem im having is finding a good downfire sub box. I want the box to go directly behind the front seats. I want a sealed box. I took the rear seat out so size is not a problem. I only have 36" of width to work with though. And what kind of amp would I need to power the subs? I am a newbie so take it easy on me.