Well this guy on craigslist seen my ad a while back about my FI BTL 18 and wants to trade me a SSA ZCON 15. His sub is in 10/10 cosmetically and mechanically, bought new 2 months ago. My BTL is the ufo style and its in around 9/10 cosmetically and 10/10 mechanically. I'm looking to down grade anyways so im able to use my backseats. But what do you think? fair trade? and how will the zcon sound compaired to my 18? THANKS!