How many watts??

Your 80 wpc amp drives your 87db sensitivity speakers rather easily at your preferred volumes; and it has reserves for instantaneous needs. a less powerful amp would be a mistake IMO.

If you like those speakers, I would be tempted to upgrade to their 9.5 speaker

https://www.dagogo.com/salk-sound-ss9-5-speaker-review/
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to answer your question:

it is Logarithmic: a lot of additional power is needed for a small amount of volume increase.

https://geoffthegreygeek.com/amplifier-power/

+3db = a perceptible volume increase. double the WPC needed for +3db volume, i.e. a lot for a little.

to double the volume needs 10x WPC. thus 10x is needed for 2X 

The great Robert Harley famously said, "If the first watt isn't any good why would you want 200 more of them?"   

This is wisdom. We have heard the amp with fewer watts sound much better in every way than the amp with more watts, over and over again. Not always! Not saying lower power is better. Not saying there are no really good sounding high power amps. Simply saying watts are not the reason. 

Maybe this related to power and sq.
I have noticed when listening at friend's system which is much more sophisticated than mine when listening at higher levels we can still talk to each other comfortably at the listening distance approx 12 feet from speakets without raising our voices too much . And the music seems more 3 dimensional.
When in contrast at my place as I turn up the volume we can't talk to each other as well.
Not sure if it is the quality of his system vs my system or room interaction his vs my room.

More than likely it is a combination of a little bit of all of those things. Detail and resolution are not just the ability to make sound fast, they are equally the ability to end sound fast. Every single component in the chain contributes in some way or other.     

More information is needed, specifically what are the speaker's rated sensitivity.

It is a hypothetical post or a troll post.
So I am not sure that more information is need? It is either answered generally and hypothetically or it is not.