not counting the number of bots deleted, lets say its over 600.
1) forums are not "upgradable". It's just part of the site.
2) I disabled the physical sign up link so the bots are not dumb: they're either sql-injecting (bad) or just directly accessing the ruby script used to create accounts. (also bad)
So next step is to take out the registration page altogether + disable the scripts responsible for signing up.