I want to replace the router/modem Comcast with a high quality for streaming

Depending on how long that audio run is you may want to consider using fiber  optic.  I had a 50 foot run of cat-6 and replaced it with a fibre optic link and it was a definite improvement.  Transceivers and cable where under $150 on  Amazon.

Side benefit of electrical isolation also.

New Investigation for myself. 

Fibre Optic vs CAT for Audio 

Being a Student is a place I like to be 👨‍🎓.

Here's are some links to the products I bought on Amazon.

Media Converter with Transceivers

Fiber Optic Cord

It can be a bit confusing with the terminology (MultiMode Dual LC Fiber, etc.)

@pindac Correct. So from your central model to your primary router you would have the single run. Then split off from there to another router. Each router either dedicated to wi-fi & data and the other to streaming/hi-fi duties. The other thing is that my wife works from home and having a separate wi-fi network for the data usage means less lag when I want to stream music since it's on its own network. 

Time Warner was nearly the death of me and then we moved and Comcast was worse.

A somewhat germain remark to add here...I heard a while back ago that Time Warner, Comcast, Verizon, etc. had a lower approval rating than congress. That still true?