Basic 12g copper speaker cables to $$$ cables.

Thanks for the help. What I know about cables could fit into A thimble, at least as far as actual experience goes Like everyone else, I can read about them online. 

So here’s what I have. Maybe someone could offer specific low, mid, and high budget good matches. I know even less about interconnect cables, so I’m open to hearing about the difference they can make and what someone might recommend as well. I have a musical fidelity a308 amp going into ATCSCM 40 V2s. It’s a very complex, difficult room, with no options to change that part of the equation.Any ideas?