@ozzy "people with no actual experience with better power cords"
Dear ozzy, please elaborate on “better” in your statement, it is not clear what do you mean. If would be good to know what cable you compared to, and what exact issue was fixed. If your “better” means look, feel, higher price, I would agree with you!
All respectful equipment manufacturers have nice power cords incl in the package, and they do design power module in the amp/pre/etc for best performance, assuming incoming power noise etc. Plenty of designs have main power module separated from sensitive audio processing unit, others have power cable attached permanently to reduce resistance. Most of resistance in AC path is not the power cable, rather fuse, power switch, power transformer winding etc. Typical power transformer used for pre has about x10 Ohms resistance, while power amp has much lower resistance in the range of Ohms. Power amp cable resistance is couple of milli-Ohms, which is 1 / 1000 or less comparing to the rest of AC path.
@facten +1
In my 40+ years professional experience, incl big shows and recording studios, I found as “hearable" power issues can’t be fixed by power cord replacement, unless power cord/connectors are broken or are not meeting spec. To identify bad cables, I use special tester with two plugs.