Most satisfying system change in 2017?

My upgrades were also extensive over the last half year, bleeding into this year.

1.  Replaced Cary tube preamp with Linear Tube Audio MZ2.  I already had the LTA ZOTL40 amp and the two LTA units together really is the way to go if the amp clicks with your speakers.

2.  After selling the Cary, I needed a new phono preamp.  Contracted Don Sachs to build me his PH16 phono stage.  Couldn't be happier, again a major upgrade in sound, maybe two.

3.  Upgraded a number of cables to Cerious Technologies.  Just recently upgraded just the speaker cables to the new Graphene Matrix line.  Wow, these were a big price jump but no regrets.  Worth every penny.  

4.  Gave my Lyra Delos cartridge a new bother, adding the Audio Technica ART 9 cartridge to the cart stable.  The ART 9 at half the Delos cost is eye opening.  I've put the Delos to the side for now.

5.  Six Vicousic DC2 diffusor panels between the speakers on the listening wall.  It was bare before.  Much better focus/imaging and they look really cool.

6.  Latest purchase, the Technics SL-1200G turntable.  This was another maybe two step upgrade over my prior Marantz table. 

Many upgrades from September 2017 to the Present:

System 1:  Replaced GE Triton 1 speakers with GE Triton References speakers, Replaced Rogue RP-5 preamp with McIntosh C2500 tube preamp, Replaced Magnum Dynalab MD100 FM Tuner with McIntosh MR88 Tuner, Replaced Conrad Johnson MF2550 amp with a McIntosh MC152 amp.  Replaced old audio rack with new Solid Steel 6 shelf rack.

System2:  Replaced Parasound Halo Integrated amp with McIntosh MA6600 integrated amp, replaced Cambridge Audio CXC CD Transport with McIntosh MCD301 SACD player, replaced Magnum Dynalab MD90 Tuner with McIntosh MR85 tuner, replaced GE Triton 2 speakers with GE Triton 1 speakers, replaced Pangea audio rack with a Solid Steel 5 shelf rack, Added platform for integrated amp.

I think I'm done and broke now.

• VAC 30/30 MKIII Signature (VAC converted my 30/70 monoblocks into two stereo amps... so I've kept one and will sell the 2nd one)
• Music Reference RM9 MKII