I'm planning on putting two 12's on my 2007 Ford Mustang Convertible. I've been looking into the 12" SSA DCON 12D4/S4 or if not, then the Street Duty SDC2.5-12-D4 Subwoofer. I don't know which one to go with or wether or not to seal the box or to port them. Any help would be great. Thanks.