Okay, my system (http://www.clubtitan.org/postt5105.html) gives me a bit of trouble with headlight dimming, and there seem to be some other power issues. The solution seems to be a capacitor. I've looked at several 1 farad caps as well as the BatCap 300. I know for the most part I can expect to pay $100-$160.
Can anyone tell me why This 3 farad cap (http://www.caraudiodeals.com/product_info.php?cPath=32&products_id=82) is so cheap? I've never had to install a capacitor before and I could use some input from any of you who knows more about capacitor brands, installation, etc. than I do. INPUT PLEASE!

Maybe it's a small battery with a small impedance... that doubles as a capacitor

That seems like a pretty good buy. You go to the Legacyaudio website and it costs $176.88.
http://www.legacycaraudio.com/list.asp?category=Power+Capacitors
I bought mine on e-bay for $30 and I think it's a 1 or a 1.5. Haven't really looked at it in over a year. But it takes care of all of your power needs.