1) Only poorly designed gear benefits from upgraded power supply cables or power source (power conditioner, etc.). If your product benefits from it, return it and get a better made one.
2) Unless you are doing a long run, EMI is not an issue unless you literally have a radio tower next to you. Even then, a well shielded cable or a ferrite chocker can be very cheap, no need to buy >$100 cables.
3) Mains noise is also usually isn’t that bad, so fixing it likely wouldn’t provide much of an audible difference outside of subjective opinions.
2) Unless you are doing a long run, EMI is not an issue unless you literally have a radio tower next to you. Even then, a well shielded cable or a ferrite chocker can be very cheap, no need to buy >$100 cables.
3) Mains noise is also usually isn’t that bad, so fixing it likely wouldn’t provide much of an audible difference outside of subjective opinions.