Gigabits of possible throughput on average consumer hardware (if your network and storage-media can cope)
BitHorde is still a single-developer project, so the easiest way to reach the developer is by mail firstname.lastname@example.org.
Bug reports and feature requests should go to the Issue Tracker at GitHub
A better way to interact with users and developers, is to join the chatroom at email@example.com. To join, you will need an XMPP Client.
If you don't already have a XMPP account somewhere you can create a account through the client at bithorde.org XMPP server.
You can also register at jwchat.org to use their web client if prefered.