According to internet tone lore, anything you change will make a difference, including changing the copper wire for other copper wire of a different gauge. Some guys even believe that cloth covered wire is part of "vintage tone".... Most seem to believe that the dime sized import pots are inferior, but IMO they work fine, and there is no need to change them. They use the same type of resistance element as the slightly more expensive CTS or other brands; I cannot believe that there is any difference in "tone" between a 500K CTS brand and 500K import pot.
Volume pots - the lower the value of the pot, the greater the overall load on the guitar's pickups (assuming passive pickups). The common values are 250K and 500K for both volume and tone; there is an audible difference - the 250K will attenuate the highs a little. In a single coil Fender, which has plenty of highs anyway, some guys prefer that. Personally I use 500K on everything both volume and tone. I tame any excess highs at the amp, or sometimes with the guitar's tone pot. YMMV
Caps - with the tone control all the way up, the type of cap should not make any difference whatsoever. The value of the cap determines how much highs are cut; the higher the value, the more dramatic the change the tone control makes; the lower its "crossover" freq. is. Some say they hear a difference with the type of cap using the same value, like paper in oil vs. ceramic disc.
Wire - some say that changing out the "connecting" wire makes a difference, like using 18 gauge wire sounds better than 22 or 24 gauge wire. I do not believe it. A pickup has something like a mile of tiny human hair sized wire; the gauge of the 6 or 12" or so of wire connecting the pots, switch, output jack just can't be significant enough to make an audible difference. I would say if someone changes wire and says it improved the tone, they fixed a bad solder joint ( which can trash tone) in the process. That, or they put new strings on at the same time, and mistakenly attributed the change to the new wiring and not the brand new strings.
The conductive paint is a method of shielding the guitar's control cavity, like using a foil. Some vintage tone nuts say that adding any shielding causes capacitance which will attenuate highs or whatever. Yes, any 2 conductors in proximity can cause capacitance, including the human body, but I am very skeptical that it would cause enough capacitance to affect audible frequencies, although admittedly I have not attempted to measure it. Most consider shielding to be a good thing, since it reduces noise, which is audible.
As you sift thru stuff you read on the internet, one thing that I would strongly suggest that you keep in mind. Be skeptical of any reviews of an "upgrade" that is usually accompanied with a change of strings; i.e., new bridge, saddles, nut, electronics/wiring, etc.
