Just here to say that the *arrs and Plex use sqlite3 databases. If these are over the network then they're going to run SUPER slow.
At least for me, when running it over NFS the arr logs were full of waiting for locked databaae and Plex started to show similar warnings in the logs after a few people were using it.
I can get 8gbps for a reasonable price. For ~30 less I'm getting 500mbps because my firewall only supports about 700mbps of actual throughput.
The home 2.5GE routers might have 2.5gig nic but I highly doubt they can support it for a sustained time.