I agree, hold on to your Avanteras for the reasons you stated. Keeping them will also provide you with a reference to the sonics of the Manleys.
The impedance curve of the Avantera III indicates it truly is a 4ohm speaker and needs some power to drive it.
"The speaker's minimum impedance is around 3.5 ohms in the low bass and upper midrange, which should not present problems to good 4 ohm-rated amplifiers."
https://www.stereophile.com/content/audio-physic-avanti-iii-loudspeaker-measurements
100 wpc would be a fine match as far as power. And nice to see that Manley provides specs for a low impedance load....
Maximum Output Power into 5 ohms: 110 Watts (1.5% THD @ 1kHz)
Maximum Output Power into 8 ohms: 100 Watts (1.5% THD @ 1kHz)
The impedance curve of the Avantera III indicates it truly is a 4ohm speaker and needs some power to drive it.
"The speaker's minimum impedance is around 3.5 ohms in the low bass and upper midrange, which should not present problems to good 4 ohm-rated amplifiers."
https://www.stereophile.com/content/audio-physic-avanti-iii-loudspeaker-measurements
100 wpc would be a fine match as far as power. And nice to see that Manley provides specs for a low impedance load....
Maximum Output Power into 5 ohms: 110 Watts (1.5% THD @ 1kHz)
Maximum Output Power into 8 ohms: 100 Watts (1.5% THD @ 1kHz)