But cat-5 cabling is pretty serious stuff, and there are some subtleties about wiring it that most laymen don't know.

Christ it's only running at 10Mbit. Cat5 is overkill.

Sure, you can saturate the hub with internet
applications, but I'll bet they're running error-correcting protocols that are
more solid and more tolerant of lost packets.

Doesn't the mark2 over ethernet use TCP packets?