I went to UPW back in 2005 and it was awesome. Met a lot of great people and still communicate with a few here and there. He does get you out of your comfort zone, be prepared. My introverted self took a lot away from that week. I flew out to Los Angeles for it. There is a lot that he talks about that "we know" but "we don't know" if you know what I mean.
The firewalking part was....wow....loved it. You probably won't feel a lot of pain when you go through it. For me, my feet began to feel it the next day. I hope you enjoy it, please post back with your report. I can't wait to hear about it.