I am looking to install a sound system in my 04 LE CC Titan. I just want to put one sub (probably 12") in the back under the seats. I was wondering what you guys would recommend regarding enclosures. Im not sure what type of box (forward firing, down firing, or upward firing) I should get. I've read that down firing boxes sound really good, but I've only seen pictures of upward firing boxes. Also, where is the best place to find them? eBay? Thanks for your help.