It's not impossible, but if you follow the pwnage directions on here TO THE LETTER, you probably won't have a problem. That's what I did, and it worked perfectly. The main part about pwnage is just not to get scared. Just let it do it's magic, and it'll turn out fine. If you really want to make sure it's okay, find someone in your local area that's done it, and see if they're willing to help you, so that you know you aren't messing up. 🙂 If you totally mess it up, not even an image will help, but if it's only minor screwed up, you can put it into DFU mode and do a restore straight from iTunes.