Yup. I bought this:
https://www.ebay.co.uk/itm/5M-0-AWG-65mm-OVERSIZED-BLUE-POWER-CABLE-5-METRES-PURE-COPPER-0-GAUGE-OFC...and had the guy cut and crimp spade connectors on to the ends. I then added bolt on bananas to the spades which work really well.
It improved the sound quality of my speakers (B&W 802N). Sounds are clearer and less congested. Continued listening and swapping back and forth reveals the same result. Others have said the same, including my wife.
For the £150 or so it cost me I would heartily recommend it.
I upgraded from Van Dam blue speaker cable.
I stopped posting on the thread as everything that's being said is just getting shouted down by a very vocal few who are apparently unwilling to believe that there could possibly be something in this. I've been called an idiot, told that my cables were crap, and that they were oxidising (they're not). The improvements were put down to me swtiching from unterminated cable to terminated, at one point.
Personally I think it's to do with argument presentation. If this had been presented as "guys, I think I might have found something, have a go, what do you think..." we would have had a lot more traction. Much like happened in the Doug Schroder Method thread. It baffles me how that idea can be so lauded and recieved with open minds when this is just met with closed doors.
No doubt I'll get a bunch of responses explaining why I'm wrong and how I don't understand anything. I'm going back to lurking. If you want more info feel free to message me.