Which is the better performer if they were rated the exact same as far as power, size, etc.? What about in a carpeted, 12x13-foot room? Thanks! ~ BTW, the two that I am considering are the JBL PB12 and the JBL S120PII. All my HT speakers are of the Studio series, and need to know which sub to get. There is only about a $120 difference (S120PII is more) and they are both 12" subs. One fires forward while the other fires down. Thanks!