Two surprising sonic improvements this year on another, similar journey:

1) After I upgraded 5000 smileys to 5200SEs in my theater at the end of 2017, I set up a new stereo system with the old equipment in an odd-shaped room with lots of stone and glass. I measured around the listening position with REW software and a calibrated mic to save an .mdat file, which I then sent to Thierry at homeaudiofidelity.com whom I'd heard about on the Roon forums. His room correction filters make a huge difference! Up until now, my only experience had been with MRC which is clearly not in the same league.

2) I asked Bruce Sinclair at CMB, who had sold me the new speakers, about power conditioning. He offered Shunyata, so I bought their PS8, Defender and Venom power cords -as I was very skeptical about this expensive stuff (and don't have Jeremy's budget). Wow! I am now shocked that M recommends against anything beyond their stock power cables. I foolishly took their advice for decades, and sincerely hope this post will save others my chagrin.

Server: Audiolinux Roon NUC w/HAF room correction and crosstalk cancellation
Theater: 218, Allo Signature, miniDSP, HD621, C61R, DSP5200SEu, 420, 33, NHT subs
EtherREGEN w/Finisar fiber, Shunyata Denali
Living Room: RPi4 Diretta Host & Target, Ghent USB > Singxer SU-6 > AES NA M-Links > DSP9
Shunyata TritonV3, LHY lps, Farad Super3, Stack AUVA feet