What are your experiences with upgrading power cords on KEF LS50 wireless?

 I sat in an hour long demo where they started with entry level cables and interconnects and eventually went up to $40K worth of Nordost.  Zero difference in sound.  

you are not suggesting that cables are a scam are you? 

Kenjit 100% a scam.  

Can I ask the question a different way?   As one who primarily believes that power cables are power cables, I also know that isn't exactly true.   For example, there are 18 AWG power cables and there are 10 AWG power cables; there are cables with shielding and cables without.  (assuming all are properly constructed with solid connections :-).

Please correct me if I am wrong, but my understanding is that wire guage can affect the amount of instantaneous power draw available to the amp; so that 18 vs 10 gauge wire could make a difference (just as with speakers).  Whether it actually makes a difference is related to how much power the amp would need to draw.  For a smaller, lower powered amp, 18 is more than enough; but maybe not so for larger, high power amps.

Here is my problem:  I don't want black cables with my white speakers.  Therefore, I will be replacing stock cables with something...

So my question is: 

1. Given the KEF LS50 Wireless II is specified as pulling 200W of power (driving output of LF: 280W and HF: 100W), is there a minimum gauge to stick with, or is 18 AWG perfectly fine? 
2. How solid is the power conditioning electronics inside the KEF?  Do I need to worry about shielding on the cable for a 6' length run in an open area (i.e., no other electronics nearby)?

Or am I off base, and my questions are just snake oil to start with... unshielded 24 AWG cord is just as good as anything else?

As one who primarily believes that power cables are power cables, I also know that isn't exactly true.  For example, there are 18 AWG power cables and there are 10 AWG power cables; there are cables with shielding and cables without.

You're right, there is a difference in the gauge. All else equal, the thicker the gauge the higher the amperage the cable can safely handle. A variant of Ohm's law is Power = Voltage X Current. If you're in North America where we use 110 volt AC wall outlets and your KEF LS50w is rated for 230 watts max, then

In North America:
230 W = 110 V x ?? Amps
230/110 = 2.09 amps

So you want a cable rated to handle 2.09 amps + a safety margin. 

In Japan:
230 W / 100 V = 2.3 amps

Europe:
230 W / 220 V = 1.04 amps

And in that case, this 18AWG cable will be extremely safe to use as it's rated for 10 amps, far beyond what the LS50w will ever draw:

Monoprice Power Cord - NEMA 5-15P to IEC 60320 C13, 18AWG, 10A/1250W, 125V, 3-Prong, Black, 3ft - Monoprice.com

I both own the original KEF LS50w and am an electrical engineer.

The only benefit the KEF cable has over the monoprice one is that it's made from that nice, soft, pliable sheathing. I've never figured out where to buy that stuff.