The amp might be going out, do you have other woofers you could hook up? Maybe someone else will have some ideas.
Audiobahns do sound good if you put them in a good box and have a good amp on them. You can�t beat it for the price. I bought 2 Audiobahn woofers for the price of one of my eclipse 10". A friend of mine was telling me how the fire series are hard to get them to sound good. I don�t know if its true or not.
www.Legacy-audio.com I have the focus's on their web site. That is what I compare my car audio to. I went to a few of legacy's shows, one in St. Augustine FL. They had the whispers set up in a huge convention hall with 20' ceiling at least and the were popping the acoustic ceiling tiles out, and yet being the clearest bass and clearest sound I have ever heard! They only had it turned up a little over half.