i bet someone on either here or roe would build you one way cheaper then any prices you said, i just don't wanna see you fry your subs
edit: i sold two 15w3's to a good buddy of mine, we built him a sealed box for his trunk it sounded great and did well.. he called me a week later and said he wanted his money back one of the subs fried and the other sounded horrible, and thats what he did he just added two aero ports to this box and poof