Most satisfying system change in 2017?

Adding High Fidelity Power cords and MC O5s to my system

Limiting the transmission of vibration from the bass driver to the midrange enclosure.  The results speak for themselves.  Don’t know what you though I was doing with the sorbothane but it works incredibly in this application.  Maybe it wasn’t clear that each driver is in an entirely seperate enclosure. A stack of boxes so to speak.
The bass driver cab vibration either cancels, blurs or reinforces frequencies in the crossover range, best to keep it out of the midrange cab. Bit like keeping your subs from touching your monitors.
i did try solidly coupling the cabinets together, it was good, but not even close to this good. 
 Btw there are quite a few designs in the market that apply the same principle in various ways.  . 

Iwal22 - thanks.  Reason I ask about cabinets is because that is what makes or breaks home built (and commercialy built) speakers.  Great drivers and well-designed crossovers in a crappy box can sound worse than modest drivers and crossovers in really good box(es). Not wanting to hijack own thread, but this gets me going.

@shadorne yes, so far its Roon by a mile.

Benchmark DAC1 ->  Benchmark DAC3 HGC. 

Shadorne review helped me to decide.  DAC3 is not only more refined but also fuller sounding in the lower midrange.  DAC1 in comparison now seems a little "thin" sounding.  Imaging is also better.  I enjoy remote with source selection, volume control, mute, dim (lower volume), polarity and power on/off.   The only negative, I found in reviews, is signaling the "state" (polarity, source, signal res/rate, mute, dim, power) by LED lights  while other DACs use graphical LCD displays.  I disagree.  LEDs not only allow for low physical size, but also are better visible from the distance.  LCD display would have to be pretty large to be readable from about 13 feet, while LED pattern, once familiar with, I can read from any distance.  I don't have analog sources yet, but getting linestage for about 10% more was investment for the future.  I also like volume control.  It is of high quality and is "hybrid"  meaning, that it adjusts digital sources in digital domain, while analog sources stay analog.  

I'm extremely pleased with the Duelund tinned copper in cotton, oil impregnated speaker cables I made, 12 and 16 gauge.