Which area of components to spend the most $ on? Boy I was wrong all my life!

Difficult to list with percentage, but the most sensible parts of the components of a hi end sistem are the recordings, the room acoustics ( dimensions and treatment), the sources ( DAC/ Players/ streamer), the AC power, Speakers and their best positioning, and class of amps ( A first ).
Cables and other accessories comes later.

A bad cable can make a great component sound mundane.  Everything matters...no free lunch!

Everything matters when building a state of the art Hi-End Stereo system. Technology is great, meaning iPads, iPhones and streaming devices for general background music. But when it comes to Listening, put a Marantz SA-11S3 in the system and you’ll Hear what I mean. Takes digital to the best it can be and in my opinion better and more lively sound than analog setups.

the Marantz SA-11S3 player is the best sounding machine I’ve owned regardless of any price. And I have owned many great ones including the $20,000 Esoteric player, etc.

On the other hand... I own a Marantz SA-10 and yeah it is wonderful etc... But my LP playback is also fine. No problems with either one.                
The great mystery seems to be... No one has figured out the one thing that made magic in THEIR system might be worthless in someone else’ system. PERIOD. I think most folks seem to get the junk some other guy found, might be no big deal. It is realizing the same is true for our own favorite steaming pile, if it were put in some other system.                      
Take for example my latest spectacular find: Refrigerator magnetic white board.. under the CD changer. I would GUARANTEE nine out of ten others(probably more!) who might be so foolish to try it would find it worthless, or terrible. Not my problem. But at least I recognize the fact!!                      
So take all your psychobabble about black goo magic cards, and whatever gizmo you found... and stop expecting to get praise as if those are the next coming. For you, maybe they work wonders... Realize the near infinitesimal chance they will do the same for somebody else.                 
So back to the op.. Glad your gizmo worked for you. No need to claim it is the SOLUTION in the Audiophile Universe to all there is.                 
(Do not mind me, I think it is the cold weather.. Cranky geesh.)

I am afraid, digital has to be quite expensive to sound acceptable, what you did you simply took it close to that.
Many good points - recording, room, level the system already at, synergy. I no longer think in terms of upgrades, I am not going to upgrade anything in my current set up, I am going to build a new system over the years, so in this sense it is going to be in a state of flux for some time but it will still be sounding better while in the process. I think, I know the destination, where I want to be with my new system, the rest are minor details. Still, if you intend to keep them for long - speakers first, then either power amp or source, both is better.