There's a measurable benefit to replacing the cable in these IEMs, if you get 4 wires all the way to the jack. The stock cables join the ground wire at the Y-split which reduces stereo separation. Enough to hear, probably not, but it will be there. This change is at least a billion times greater than what kind of wire is used
I like cables that are well built, durable, aren't microphonic, don't coil up or are an annoyance. It will be hard to improve on the stock cable in any of these areas.