I know that Joseph Chow (Audio Horizons) has developed a ZP80 power supply upgrade which I am beta testing. It delivers a significant improvement to the music. My reference for comparison was a Levinson 37 transport which had been upgraded. When Sonos performance matched it, I sold the Levinson.
I use FLAC files from a network storage device, and play through the ZP80 digital output to an Audio Horizons tube DAC.
In order to get the best signal, both the transmitting and receiving ZP80 power supplies should be upgraded.