I don't know anything about these Arc series subwoofers. Does anybody know anything about them or have opinions on them? I don't just want the info that I can just read from their Arcaudo.com webpage. I ask because some guy is selling 2 of the d4 12" for $200, so I wonder if that is a good price. I'm currently using a single 12" alpine R. Worth switching for the 2 Arcs?