I typically listen at -6 to -3 & the occasional 0.
After you get the amp, please let us know if your volume is still -6 to 0.
DenPureSound as a great reason for getting the XPA-5: his Denon 3311 goes into protection mode without it!
And as PENG says, even if Dennis' AVR3311 did not go into protection, he was probably getting plenty of distortion @ >/= 0 volume anyway.

So the XPA-5 greatly alleviated that.
My family room is 18' x 20' x 10' ceiling, open to 3 sides. From 2 meters, with my Denon 3310 @ -10dB vol, I get 85dBA on Hotel California. But this is in 2.0.
Dennis is using 7 Ch Stereo Mode.
So there is definitely a place for ext amps.
I'm glad Emotiva is making affordable powerful amps for a lot of people.