@capt57 Topline (8 ohm) output means very little if the speaker is lower impedance. It means more current is required and its rating and ability to handle lower impedance is far more important. In the case of the Aethos, it needs very easy to drive speakers or it is going to over-heat according to the manufacturer.
The Supernait is rated to 2 ohms and is designed to be paired with Focal. They are relatively difficult speakers to drive with impedances that will bottom out below 3 ohms. The 805 D3s will be an easy load on them.
The difference between 80w and 125w in terms of peak output is about 2 dB. At 80w, the B&W will output 103.4 dB at 10' and at 125w, the peak output will be 105.3 dB. In the extremes it will make a small difference.