Eliminate most of the wired Ethernet issues by simply earth-grounding the DC common of your router. Tie the DC common to the ground pin of the IEC connector, either inside the LPS you are using, or by using an external wire to the third hole in the AC outlet. The Sboost is a good choice because it has fast regulation but I don't think it is earth-grounded.
Another thing you can do to help is to add a EMO EN-70e isolator in the Ethernet cable.
I do both of the above. Works like a charm.
Steve N.
Empirical Audio