I was browsing through ebay today and saw that Kicker has a pair of 15" L7's up for $400+S/H. The only thing is that they're listed as "refurbished" and don't really know what to think about them. Here is the link Kicker L7's. I'm not exactly ready to invest in a system yet but it would be nice to know for when I actually have all the money I need together.
