You don't absolutely need PH/mysql for creating an autoupdater, but it would allow you to track stats, I guess. All that's really needed is a simple text / xml file that contains version info.

If you want to get even more advanced, perhaps you could look into generating file checksums so the entire game doesn't have to be downloaded every time -- just what's changed.

As for unraring, I doubt there'll be many components that do that, but there are some that do zipping. I've only fiddled with one zipping component so far, and it didn't support compression, so read the release notes of these things carefully.

And for networking, there's of course lnet, indy, synapse...