For sale is a lightly used Tang Band W5-1138SM sub-woofer for sale (
http://www.parts-express.co...cpc&utm_campaign=pla ). I had it in my Fiero's stock sub-woofer enclosure for about 6 months before upgrading my sound system. The sub-woofer was never abused and sounded great when taken out of the car. If you're unfamiliar with the install you can read more about it here:
https://www.fiero.nl/forum/Forum3/HTML/000079.html I am including a piece of 1/2" MDF that could be used to mount the sub-woofer though I would suggest getting a piece of 3/4", I just had some laying around and figured I'd throw it in.
$40.00 Shipped in the continental U.S. and it's yours.