i have a single Powerbase XS 15 coming and want to make a box for it but have no idea where to start. It will powered by an XTR Pro 2400 going in the trunk of an 02 Grand Prix. on the site it says for 4.5 cu. ft. internal, and a slot port of 36 sq. in. x 15" long. Does that 4.5 cube internal space include the port area, or do you have to figure that in too? That is for the recommended tuning of 34 hz. Also, would it be benefical at all for to tune a little lower, i was thinking maybe 31-32ish, i wanted it be able to play low also... It will be for daily driving, no comps at all, i just want it to sound good and get pretty loud also. Thanks, any help is appreciated. If anyone is willing to give me the exact dimensions of the box with all the measurements using 3/4 MDF i can paypal some money over to you for helping...