I wish this were true, nobody would like it to be true more than me, but I still think this is a very tough matchup for GSP.
Obviously he has ways to win, but bottom line, in that fight, size will matter. If the skill is equal, or close to equal, size really matters, and no matter what weight they fight at, if they fight, Silva is significantly bigger, minimum 10-15 pounds, probably more like 20.
GSP can outwrestle Silva, obviously he can, but he has to get Silva down to do that, and has to do it without getting hammered. I love me my GSP, but thats a tall order against a guy with Silva's reach and size.
And the fact GSP is a such a good striker in some ways might make it harder for him. I don't agree that Sonnen's boxing is that good at all, I think Sonnen just had some success because he was fearless and caught Silva off guard. Well, Silva sure as hell won't underestimate GSP that way.
If Silva is careful and uses his reach, I think he can make life awfully hard for GSP. GSP has awesome speed and power, he could get Silva down and keep him there, but if I have to bet on someone, I'm still betting on Silva, and thats coming from a huge GSP nuthugger.