I found some newprefab subwoofer boxes custommade for these trucks( sometimes these things are hard to find), and they are sold for a great price!I putthe post and linkin the audio section but its not getting many hits or any posts, not sure if any of you guys are into that kinda thing or not so you might not visit that section. If you are go check it out. I bought one myself, pretty good stuff.
http://www.subthump.com/