Stoney, as Ken indicated, the receiver doesn't "drive" subs with built-in amplifiers such as the EP-500; it just feeds it a low-level audio signal, but no power from the receiver is used.
On the auto provisions, don't mix up the two entirely different features that are involved. The automatic calibration of speaker levels and distances does a fine job, at least as accurately as could be done by a manual calibration with a separate sound meter. The automatic equalization(if present)is more controversial; some have reported improvements in sound, others have reported that it made it worse.
