The "most foolish" loudspeaker tweak/upgrade ... is

1) twisting makes a difference.

2) the same twist tightness throughout the entire length of the cable is retarded.  You want a tighter twist on one end than the other.

3) the higher end your system is, the more these minor tweaks are audible. I've got a reference system and I can hear the difference my cable risers make. I could not on a cheaper one.

@cdwallace3 Not quite. The primary factor (imo) is speaker efficiency.

If you have 102db/1w speakers (as I do), then their sensitivity to upstream changes are huge.

The more efficient your speakers, the more revealing they are.

That said, you’re not going to find high efficiency speakers that cover a large frequency range w/o spending a fair sum.

I got really lucky and got a pair of eXemplar Horns used. John Tucker won’t build another pair for less than $35k these days.