BassAddictJ 5,000+ posts
CarAudio.com Veteran
i'll do them for free. i was gonna get an 18" xxx for my jeep back in the day and had a box plan i made that was 7.5 cubes net tuned too 35 hz. with about 120 sq. in. of port area.
THAT + http://www.accelerator-pedal.com/ported-box.asp = easy way to design your own box.