If you're worried about the FBI putting backdoors into your IRC client, you've got bigger problems on your hands.
Unless you're using the (rarely used) SSL feature in mIRC, everything you say is sent clear-text. You'd better worry about the people running the 30 routers between you and the other person monitoring your communication.
This is why everyone says 'don't give out personal info'- because it goes through about 100 people to get to its destination.
If you're so paranoid that you're worried about backdoors, perhaps you shouldn't be on the internet.
