I currently have 4 re sr 12" subs, they are loud but not really impressively loud. I thought 4 sealed subs wold beat wAy harder than they do. They are hooked to a vlx 2de so they are getting about 150 watts a piece over spec. So I'm wandering if two sxx ported in 2ft^3 a piece would out jam the 4sr's. They rated at 1000rms would 900wAtts a piece be enough? Are they good subs?