Ethernet

I am also interested in this issue, as building a new system and considering the Lumin T2 with Roon.Beside the quality ethernet cables I was recommended to add a fiber optic bridge or isolation between the router/switch and the Lumin, for example 2 Sonore optical modules.
The Lumin X1 has a fiber optic commection built in, so I assume something similar would help with the T2 as well....?

is there a significant difference in sound quality between audiophile grade cables and switches as opposed to regular cables and switches?

Yes. Significant.

I had connected my Streamer-Dac box via ethernet cable direct from the router using a "generic" cable. Once I changed to an Audioquest shielded Cinammon cable the sound difference was immediately noticeable and it was a good difference. I suspect shielding was the big reason.

As far as cables are concerned, there is no benefit from “audiophile” cables. You can and should buy brand-name, factory assembled and guaranteed cables such as Leviton or Hubbell. Home made cables where you crimp your plugs on to no-name chinese twisted pair cable of unknown quality are to be avoided like the plague. Cat5E is more than sufficient. Cat5 is sufficient. Cat6 is good but not a requirement for gigabit Ethernet. 

Don’t waste your money on “audiophile switches”. Avoid big box and dinky computer store switches such as “Assus” and “Toilet Paper Link”. The important thing is to use a good small business grade or enterprise grade switch that is QOS-aware. This means that it will give priority to packets that are tagged with a high DSCP over non-time-critical packets like HTTP and SMTP and POP3. There is a plentiful supply of off-lease enterprise switches (ie: Cisco Catalyst, HP Pro-Curve etc...) available at 5 to 10 cents on the dollar compared to brand new. 

sleepwalker
As far as cables are concerned, there is no benefit from “audiophile” cables. You can and should buy brand-name, factory assembled and guaranteed cables such as Leviton or Hubbell. Home made cables where you crimp your plugs on to no-name chinese twisted pair cable of unknown quality are to be avoided like the plague. Cat5E is more than sufficient. Cat5 is sufficient. Cat6 is good but not a requirement for gigabit Ethernet.

>>>>Are you talking about cables or wall outlets? Maybe Leviton and Hubble make cables, I guess anything is possible. 😛

In my experience, there's a BIG difference. You really need to use high-grade Ethernet and USB cables to get the best out of your streaming setup.

In my system (Atma-Sphere, Sound Lab, Eversolo), I'm using cables made by the French company MissingBond, which are outstanding and relatively inexpensive. Previously, I was using the AudioQuest Diamond (€1500), but I find the MissingBond Ethernet cable even better—while it costs only €300. One of the best buys I have ever made!

Replacing standard inexpensive cables with properly shielded Ethernet and USB cables dramatically improved all aspects of the sound in my system.

Don't listen to people telling you things like "cables don't matter." They do—much more than we usually think!