Regarding buying a receiver with pre-outs and adding external amplification, not all pre-amps are the same. I don't know if any of the big name receivers have quality pre-amps. I recently discovered this and now I am on the hunt for more pristine electronics. The electronics have become the limiting factor in both of my v4 systems.

House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated