When I got my recent speaker cables from Anticables, Paul Speltz mentioned he was including some high quality jumpers with the cables.
I’m currently using them because I have them, but I did try the old cheap speaker wire ones I made 15 years ago and didn’t notice any discernible difference. I do my best to be an objective, ear driven tweaker, and didn’t notice any change. Maybe my juvenile ears just aren’t fine tuned enough for the subtle tweaks yet. 