Do pure copper banana plugs make a difference in the quality of the speaker sound.

Minimum mass copper or brass crocodile bananas, crimped, not soldered. And to make them connect: Acoustic Revive ECI-50.
Truly secret sauce territory for connectivity.

"Minimum mass copper or brass crocodile bananas, crimped, not soldered". might you have a link to that? AND do you think that bananas are better than spades? when i went to high quality 10 gauge wire, i could hear the difference over what i had before. im just looking to do what i can to get as much improvement as i can, without the snake oil!!

Wait, that acoustic revive is 500 bucks, and 55 dollars shipping?  uhhh, no.

https://www.dienadel.de/en/acoustic-revive-eci-50-highend-contact-spray-50ml/a-353635163

https://compassaudio.co.uk/product/bfa-banana-plugs-beryllium-copper-gold-plated-z-type-connectors/

The Acoustic Revive stuff is outstanding: treat all contacts incl. fuses and you’ll find it one of the best value or money tweaks anywhere.

Otherwise Chris Venhaus at vhaudio.com can probably help

The best connector is no connector, if your binding posts can handle that.

Yep, it seems the quality of the connectors is much more important than the cable between them.  If you calculate the right gauge, any cable will do. But the terminus is the thing. I run the cables all the way to the driver and solder the connection - the advantages of building your own. Soldered banana plugs the other end so they can be easily cleaned.