Are manufacturer AC cables good enough?

Rule No. 2, Never ask geoffkait.

@cd318 --- I knew exactly what you were going to say. And I regret even trying it. Carry on with the snake oil theory. In fact, if you are so convinced with said snake oil theory, why do you even participate in cable threads?

P.s. you missed #3, with a reference to #1. That was the answer to exactly asked you in the first place: "... In the meantime not one credible explanation has emerged as to why the last 2 metres of electrical cabling should matter exponentially more than the previous possible kilometres."

the power cable presents a high impedance to these signals they will be reflected back into the power supply

That's easy enough to figure out just measure the $$$ aftermarket power cable and the stock cable that came with the amp and see if there is a difference.

Misconception #3 is nonsense audio components don't have perspectives but anyway why 6 feet? Suppose your magic cable is 12 feet does the amps perspective change? Lets make the cable 30 feet and connect to the panel box what's the perspective of the amp now, does it know a breaker and bus bar is now the bottleneck? What's the perspective of the wires after the power supply? Complete idioticy.

thyname

... In the meantime not one credible explanation has emerged as to why the last 2 metres of electrical cabling should matter exponentially more than the previous possible kilometres.

Logical fallacy alert, straw man argument. I don't recall anyone here claiming exponential improvement.