Learn, Learn, Learn
About conductor material, dielectric materials, shielding materials.
And how these things affect performance based on:
What they are,
how they're laid out (topology)
How they're connected (especially shields)
And if you don't want to learn, you have three choices:
1.) Buy the first thing some Agonner says is best.
2.) Stick with the OEM cord.
3.) Buy the biggest gauge (like 10AWG), unshielded cord, you can find and it will probably do just fine. Why "unshielded"? Because the shield (if it is shielded) might not be connected in the most optimum way, and you'd be in no position to tell; with the result that it could cause more problems than it solves.