If GSP can take Silva down he would probably have a very good shot at winning a decision, if not he would likely get destroyed on the feet. I think it could be a competitive fight and it is a fight that a lot of fans want to see. The winner would probably be the undisputed p4p king for now. If Silva wins that fight, I think he should go up to 205, as there would be nothing left for him to accomplish at middleweight, and I can think of a lot of good fights for him at 205. Also, keep in mind GSP has to get by Jake Shields to make this happen.