Most satisfying system change in 2017?

Finally finding and buying the Krell B&W Bass Alignment Filters  pair (balanced) for my B&W Matrix 800s..  Now its time to relax and really hear what these baby can do !!!! 

Not much to report other than a 1.5 meter of the new MIT Heritage series interconnect, an EVO 2 between my preamp and amp.  The best MIT IC I have had, equal to my 350 SG EVO. 

The marketing machine at MIT is truely delivering some trickle down from it's uber priced reference line.

DIY US cleaner
K&K Audio Trio phono preamplifier
New found replacement tubes for above
Minor speaker adjustments

I upgraded my HT by replacing Klipsch KG 4.2's mains with Klipsch Rf-7's. I also found 3 RC-7's for center and surrounds. And I replaced my dated Onkyo with a Denon Avr-x4300, and a basic Sony bluray with the UDP800.

Everything blends nicely sonically and the sound is the best I've owned. And, even though my 65 inch Samsung is only 1080p, the picture has improved with the 4k upscaling and with 4k discs too. It seems the higher resolution provided by the 4k disc allows my tv to live up to its maximum potential. Next year I will buy a Sony or Samsung 70ish inch with 4k and HDR. I'll have time to acquire a collection of 4k blurays.

Nice thread @knownothing!  Thanks for starting...

2017 brought in quite a few major changes in my system, like some others here, and I can narrow it down to my most significant changes..... 1st, going back to 300b based SET amplification (Coincident Frank mkIIs), secondly, adding an amazing and fantastic sounding preamp to the mix (the Backert Rhumba 1.2), and finally cabling that tied it all together (Cerious Tech Graphene Extreme speaker and power cables, Teo and HFC ICs).

2018 will be a year of “enjoying and discovering more music”. Not that previous years weren’t, but I don’t anticipate any major changes for the foreseeable future.