Right now I got two 18" BL's in a wall behind the 2nd seat of my explorer, thinking about adding another just dont know if it will be worth it. Planned on taking the wall with the 2 of them out and then trying to fit the three subs aiming up with the port back. Pretty much just need some more people to make me feel better about spending the money to do it lol, if it will be noticable enough.