I am using Silver module and yes, these modules provide different isolation and hence different bass response. Start with silver and then roll them to see for yourself.which module do you use the xenon 6 with? how big is the difference between them? does it only affect the sub bass? what material is the factory cable made of exactly? can it be bought separately? if so, what is its exact name? is there an audible difference compared to custom cables, or is your factory cable already high-end? I somehow find it hard to imagine that they create an IEM with such amazing sound quality as the xenon 6 and degrade its performance with a bad factory cable.
here are the details of Fir Cable and yes you can buy a cable on its own.
https://www.firaudio.com/store/fir-cable
Default cable is good and you can just live with it and not worry about changing cable unless you hang around threads where someone will say to get better cable to get that last 0.005% out of your IEM.