As I mentioned before, all tube and some solid state amps have a power transformer which literally isolates the power line from the rest of the electronics.
Unless somehow this new fangled power cord overcomes the laws of physics, there's no way it can have any effect.
Here is an excerpt from their website they explain why it's better:
"By increasing the surface area of normal round wire tenfold or more, skin effect is no longer an issue."
Are they joking?? Do they (or anyone else) know what "skin effect" is? Well boys and girls, I do!
I was an amateur radio operator (WN2CMF) and built my own 40 and 80 meter transmitter and receiver, and studied analog RF theory, I know what skin effect is! It mostly applies to frequencies in the megahertz range and higher, where it has a significant contribution to transmission of signal. Skin effect is when the frequency of the signal is such that the electrons (yes, electrons are what moves to create a flow of current) move to the surface of the conductor away from the center. This is why waveguides in the gigahertz range are actually hollow tubes.
So, obviously the 50 or 60 hertz frequency of the power line has such a negligible effect on the migration of electrons to the "skin" of the conductor that it has absolutely nothing to do with the alleged improvement! Period! Their claim makes great advertising black magic, but has no scientific basis.
They even named it appropriately: Grand Illusion! How ironic.
Besides, who would pay $1,700 for a 4ft. length of flat copper conductor you can make yourself for $25?