You will want to reinforce the inside walls. Prefab boxes have nothing more than screws and maybe glue holding them together. SO when the bass gets up, so does the flex in the box. Eventually the face, and sides of the box will begin to seperate. I haven't personally heard Diamond Audio, so couldn't tell you. The subs we mentioned before are good for your application. Don't underestimate the Kicker CVR.
Well that I dunno, how much room is under your seat?Anyplace that sells them will list the mounting depth of the sub. Just make sure that depth is atleast 2" less than whatever the height is under your seat. As far as the JL's go, never owned one, nor ever heard a w3.
