Hi Brian,I agreee with Arky , what you put into the klipsh is what you get out, you won't go wrong with the 7125, it is what I use and my room is similar to the size of yours 14x 20 with a 13 foot peak in the ceiling and I no problems driving my klipsh and the rf-82's are more efficent than my 35's good luck.
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Outlaw 990/7125,Denon 2910,Toshiba A3, Klipsch RF35,RC35,RS35,RW12,SMS-1