Now that I'm back at the house...
The Amp stage of the AVR or any outboard amplification has no impact on Subwoofer SQ. (On a tangential mini-rant, please don't look at Sub amp wattage as a worthwhile metric, and please keep in mind that timbre-matching Subs to speakers is not a thing
Now, your very last question:
Are you asking about amplifying these with an external Amp? Or was that about timbre-matching (see above