Any amplifier utilized for full-range work must provide substantial power for low frequencies while also providing clean and fast transients for high frequencies. Outlaw amps do this well, likely better than most AVRs.

However, if one wishes to use HDMI audio and/or meaningful electronic adjustment to aid in room correction, one would need something other than an Outlaw product to take on the processing duites.

I think almost any AVR will benefit from some reduction in 'power burden' by at least sending the lowest frequency power demands to a powered subwoofer or separate amp/sub combo; fast transients would not have to ride on top of the largest power fluctuations. If one uses a separate power amp (with or without a subwoofer taking on the lowest frequencies) the power stage of the AVR may still be following the voltage of any non-subwoofer freqencies, but the AVR is not trying to deliver strong current or fast transient changes in current, and the AVR power supplies are practically coasting.