"I've swapped some high end and less so cords in and out for fun and it pretty much always sounds great regardless."
Power cords and similar fringe tweaks have the advantage of not having much down side. They all work pretty well, but performance of gear can certainly vary to an audible extent that might still be better or worse in any case depending on what on starts with and then changes to.
But the differences are subtle on the large scale of things I would say, so its hard to go away unhappy because a power cord ruined the sound.
Same true with other tweaks targeting "audiophile" kooks like us ranging from fringe-to-placebo IMHO like isolation devices, fuses, clocks, flying saucers, even ICs though to a lesser extent perhaps.
At least with wires, fuses and other actual electrical devices, its not as much of a stretch to envision how some difference might result, though proving cause/effect conclusively when it comes to effect on sound quality is elusive at best.