Well I have had my experiences with subs and have had the loud boomy subs and have had the tight responsive subs. I prefer sound quality over SPL. If you want to be heard 2 blocks away get a ported box and some subs that are for SPL(2 15" eclipse titanium). Now if your not looking for that boomy bass get a smaller sealed box and subs aimed towards sound quality. I would recommed 2 10" or 12" eclipse aluminum, boston, infinity perfects or JL W7 if you have the money. I think the eclipse alum and boston are really nice sounding subs aimed towards sq, but will also get loud.
The eclipse has a huge magnet...cant remember how big, but it would require a lot of power to get it moving. Hope this helps.
Face the subs towards the back...so there facing away from you (if you open the trunk theres facing you).
