My vote is Anti-Cables speaker wires .. they blew away way more expensive cables I had like Audience AU24, and the 3.1’s only cost like $300 or so. I’ve never tried their interconnects. I use Acoustic Zen Absolute RCA's which are amazing but pricey.
The AntiCables are so inexpensive to buy direct just to even try them, and I think they have a 30 day no questions asked return policy which you won’t need