what i was told: audiobahn's subs are only good when you get up to the top. they are more expensive.. then again the way i see it is if your going to spend so much on a rinky dink sub you might as well splurge for a good one.
I have a pair of audiobahn aw1200's. I have had them for over a year and have never had a problem with them. They are really loud, but not as accurate as some others subs. You can get a pair of nice aw1200x of of ebay for about 200 dollars shipped. The x is this years model and without it was last years model. You can also go to http://www.carreview.com/Subwoofers/Audiobahn+AW-1200/PRD_3739_1808crx.aspx They have alot of good reviews.
Audiobahn subs have really good SQ, not to mention they hit pretty hard too. I have an ALUM12 that is running at 980 watts...everyone asks me how many twelves i have...and they are blown away that i only have one. they arent that expensive, especially for the SQ