Why ported!?
Doesn't anybody aim for sound quality anymore!? :hehe:
Firstly, you need to pull out the spec sheets on your subs to determine the proper diameter and length of the ports. And, if the enclosure is enough. Btw, most subs are made for a variety of box configurations. You may misadvertently tune the box to an wanted frequency. Once you know what's necessary, you can move on from there.
See the I/A/S FAQ for some sites for accessories (I'm pretty sure they sell accessories, too) as well
www.selectproducts.com