Hi Jim,
We could not agree with you more! A custom enclosure is very important, especially if you want more sound directed into the selected room versus out the back wall. These are actually excellent woofers at factory-direct pricing. Even if you add the cost of the custom enclosure, it is still a great value. I believe these subs are considered an infinite baffle so they can work in a number of different size applications. We do not have the Theile/Small parameters but will try an obtain them and add them to our features and specification on our site. Iwill try and email them to you as well. We would be interested in what design you come up with. Perhaps you could post some pictures for us.
TL/MA