I have prewired my living room for a Dolby 7.1 setup. I am considering several options for a moderately priced 7.1 system. Does anyone have a Polk RM7200 system set up for 7.1? Would the RM7200's sound fine in a 13'x17' room, or should I step up to the RM7600s? I can't seem to find any place local where I can audition these systems, so any input would be great.