Well, quite a big reveal hmm, I'll say this about pirated software, we've all been young and done things and felt bad about it so we fessed up and did the right thing that's okay no judgement, but at the very least, you run the risk of being outed and banned if caught (using a pirated disc), you could be banned by ip from Steam service(EA got a lot of people a couple years ago with the Medal of Honor Beta and using it as a Hack tool) pirated software usually is incomplete or almost impossible to update and may contain some unwanted "passengers" in the code...end of sermon
that being said it's good to hear that you took the plunge anyway and decided to suffer with the rest of us.
Read the Forums I'm sure once you're installed you'll have a bunch of questions, most of us who have the game have had our share of issues but it is possible to get it running well enough to enjoy and the latest beta patch looks promising. As for modding CoD is supposed to support it but it's a little early yet. Still I have no doubt people are already working on that aspect and if the Il21946 mods are any indication there will be mods for Cliffs. Once you get it set up I'm sure you'll be able to get some of your questions answered. Welcome to the Battle!