What is your approach to system fine tuning with cables and cords ?

Last year I stated upgrading my Magnepan 3.6 to 20.7s. I like the 3.6 sound a lot. just mainly wanted the greater clarity from the different designed midrange in the 20.7s. After I bought some slightly better powercords. The powercords made me want more.. Since they did improve the sound. In between my dealer loaned me a digital player, which I bought one of those too.
Back to the power.. Some Furutech AC duplex were on sale and I decided to try a few. When those made a noticeable difference to the good. I bought a few more. Then a few more. and then few more.. adding the duplex even inside the two power conditioners I use. And then even better power cords on sale.. So I bought those.. Finally some AC noise remover gizmos on sale. I bought two, yeah they do good stuff, so bought five more. (borrowing a noise sniffer from my dealer also helped me to place the noise removal devices)
So some of the upgrading was buying stuff I thought about, but since ’on sale’ time to do it instead of waffling maybe later.. (rare on sale meant buy now). My main interest was clarity.. Better seeing into the music. Like vocals, on Rock became clearer, Startling realistic midbass...
Anyway, during, in between, and after buying all that stuff, I was adjusting.. Swapping powercords here or there to adjust the tone.. Even the fact I had dual pairs of duplex for the amp.. One Furutech GTX-D Gold, the other a Furutech GTX-D NCF Rhodium.. and swapping the powercord plug from one to the other changed the tone slightly overall (curiously while breaking in, I liked the Gold better, then the Rhodium, then back to the Gold.. but once the Rhodium finally was really broken in, it is the one I use all the time now).
One reason it was easy to for me to hear differences.. My drive for clarity brought the sound to the edge of lean over and over.. keeping it warm enough with the clarity uppermost was the challenge. So the sound has been on this edge for years.. Finding ways to make it warm up a bit and still keep the clarity. So I am really used to hearing this and able to make adjustments to bring it back to warm enough to make me happy, while still having amazing clarity. The last things I had been moving were a few powercords. Two were DH Lab $8ft wire with Furutech ’28’ plugs, two Pangea AC9SE mk2 Signature, and two Pangea AC14XL. For amp, one preamp, and the Furman conditioner power cords back and forth to find just the right best sound. Ending up with the AC14XL on the amp, The DH on the Furman and preamp, And the AC9SE Sig to the Rudistor RPX-33 headamp. trying stuff all over, and not just where some guru theory sez’ it should go. So in particular a heavy amp cord on the little headamp? and a smaller 14 gauge on the main amp... SOUND not theory placement.
(Just to note I had previously bought way better IC a few years back, jumping up to Kimber KS1016 and KS1116 series IC which I felt would be good through any future upgrades..)
I hope this answers inna’s question a bit.

I guess I do want what I like, not what someone ELSE likes, is the difference. True I do concentrate on a few aspects, making them as perfect as I can.. Many other aspects follow along anyway, particularly a quiet black background. So I really do not need to address them. Some areas I care little about are super dynamics, and bass, also even frequency response, whatever it is is good enough IMO. In fact I despise gut massage bass. and would never have it. Just my choice of speakers, Magnepan clearly no bass driver attack whacks needed in my system.. Actually to the point i have deliberately reduced the bass via power conditioning and wires, from what can be had in a pair of 20.7s... Back down to about what was in the 3.6 I had before. though with a bit more midbass bloom and finess .
I can see your point about modifying the system. but realize the mods go all ways..To do what YOU WANT, not what some guru orders you to have.. ’or else’. All these things are subtle, so a non audiophile would never in a million years notice anything different. So for folks who love gut massage bass, from my modifying, I could tell them want to do to add to it! s well as reduce it.Clarity is what I have chased because I love it. I enjoy it. And the enjoyment is the key If I were somehow required to have only what some other person wanted. I probably would has settled for a cheap all in one system and saved $50,000. Some folks chase a standard dream. perfect sound true to the origin. Some understand THEMSELVES better, and chase what they really want. If in some audiophiles eye that makes me a fail, not my problem.

Now that I have the actual equipment pretty good. I have been starting to think I should do something for the room, at minimum the wall behind the speakers. Being a very large picture window. The first thing  I would do is below the window, to the sides of the in wall air conditioner, some wood block diffusers.. I would hang them from the window sill, as they need to be above and enough behind the full length floor heating element to not block the heating unit.  Some things cannot be done to the windows.. rules etc. But I think I could make something right at the window dividers to help dispersion. Something vertical with lots of diffraction, at most a few inches wide. (if  I worked on it, perhaps actually framing the Windows by maybe two inches? Finally, above?? Something very light, I can make a beam full length carried at the far sides by the bookshelves at the corner sides..  with diffusing elements attached to it.
Currently I feel there is too much sort of reverb off the back. So possibly just the things I am considering would be enough, without actually blocking the windows more. Which, like a wrote is not really allowed. (drapes are permitted but I will not close the heavy drapes I now own, for a variety of reasons. mainly pets.) All that is a thought experiment.. Maybe eventually I might do something.. maybe.. I am in no hurry.

blindjim comment about something  sitting on window sill.. I have a few silk plants in vases. a mid sized sculpture, and a narrow large one now. But just now thinking maybe more.. I thought why now find a pair of larger rectangular-ish cheap vase and add irregular small blocks of wood, covering it fully to make a pair of free standing diffusion devices! with the silk flowers.The vases would fit within the window rules...