You'd be better served with something like Heresy's, Forte or Forte II, Epic Series CF-3, or KLF-20's. Those would be about the max size that room could possibly support. You need a certain amount of distance for the bass wave to project or you're going to have odd "nulls" in the room and poor bass response in one spot and a lot in another. Not to mention poor coherency in sound. Silver series receivers like those, especially Pioneer, don't seem to fare well with Klipsch Heritage. Not to mention you don't need that much power. I don't miss owning big silver receivers....even the SX-1980 I had. But the Harmon Kardon Twin Power 430, 630, 730, and 930 are known to mesh well with Heritage.
But it's that room size that's the kicker here.