I also visited Lubomir and the M101 room. He is super friendly and spent much time with me. Yes the difference between his ethernet cable vs standard LAN cable was easily appreciated and significant. He stated his good cable should be the last cable entering your streamer.
Currently, I use the Network Acoustics Muon Pro ethernet filter just in front of my Streamer. I believe he said they both cause improvements, and NA does include their own proprietary cables on each side of the Muon filter box. The cable leaving the Muon (entering my Grimm MU1 streamer) is fixed and can not be changed. My LAN cable reaching my audio system is long, using Supra CAT 8.
So my obvious wonder is where would a M101 cable be added and what would be the expected benefits? I should try one...
And, I have always found the Persona 3F's bright and glaring. Not so with his loom of cables and the tube amps he was using!