I saw here on this forum some time back that someone had installed their subwoofer into the spare tire well. Is that thread still around? or does someone know how to do this?
check out http://www.coolcats.net/eric/86convertible/1996_2000.html
down a ways is a picture with this ecplination. There used to be a write up on it but I cant seem to find it.
Out back I built a permanent subwoofer box into the trunk well. This helped me save usable space in the trunk while still having bump. I also moved the battery to the back to help with weight distribution. This was a cool idea at the time....for me, though, it proved impractical.
Here's a setup I did in a Honda Civic in 2000(not my car) I raised the floor about 4 inches to get the required enclosure space for the speakers (15" JL audio) I used about 3-4 layers of fiberglass matt to make the spare tire enclosure sturdy-so it wouldn't vibrate. It's not a bird but you get the idea. The space in the bird is very good to work with-I believe you can get it flush with the surrounding floor.
If you really want it in the spare tire location, you can make a fiberglass enclosure to fit that space. Try Mp3car.com (http://"http://www.mp3car.com/vbulletin/fabrication/") or the12volt.com (http://"http://www.the12volt.com/installbay/forum_topics.asp~FID~16"). Let us know how it goes