I dont really have much room to play with because it will be going under the rear seat. I don't really have a lot of money either but I want more than what the JL W3's are giving me. Maybe I have unreal expectations, but I have heard so much good stuff about JL, that's why I chose them and the guy helping me is really big on JL, in fact he held the world record for 3 subs without a wall in a yukon he built, granted it had 3 13W7's and 3 JL 1000/1 amps and focal mids and highs etc., but back to my situation, how much can I cram under the rear seat? Should I look at some of the shallow mount subs, or what kind of box could be built? I have no box building talents!