Before you suggest high dollar cords, please know that I'm not a skeptic, but am tapped out for power cords. And, for what it's worth, I had a Pangea AC9 1 meter power cord which I experimented with using my REL. Made zero difference. In fact, in an exchange with REL, they said this: "A while back, REL tested some third party power cords with our subs but did not find a noticeable impact."
So REL tested "some" third party PC and "did not find a noticeable impact." Probably because power cords tend not to have a noticeable impact with subs. Another example of just how different low bass is from everything else.
Look at my system.
https://systems.audiogon.com/systems/8367 All that crazy stuff- Cones, elevators, tweaks of every kind- every single one of them was tried and compared and proven or its not there. So what's not there? Check out the crap IC going to the subs. Cheapest IC in the system. Absolute trash. Tried a bunch of others, no difference, so trash it is. Subs don't care.
Notice Electraglide fat boy PCs going to the Dayton sub amps? Know why they're there? Because I had em, just sitting in a drawer, and they're the perfect length. Only reason. Notice cheap gray crap rubber power cord going to the Talon Roc sub? Guess why. I had it. Its long enough. It gets power to the sub. Save your money. Buy whatever extension cord you can find that's decent gauge and save your money for where it will make a difference.