As much as I believe that GSP is the legit #2 pound for pound guy, I wouldn't give him more than 20% chance to win in this match up. GSP doesn't bully and tackle his way to a takedown the way Sonnen does, for him it's more about his opponent over extending or making a mistake (usually because of excessive aggression). I don't see Silva doing that.
Not saying that GSP wouldn't eventually get a takedown or two, if he survives the damage he'll likely take to get one, but once it does hit the ground he doesn't have the power to finish Silva. Actually I don't believe he has the power to finish Silva anywhere, on the feet, on the ground, through cuts nadda.
But we all know Silva has the power to finish GSP ANYWHERE. So when you take into account all these variables there is no way that Silva loses this.
Mental game (confidence and psychology) - Silva
Finishing ability - Silva
Heart - Silva
Stand up technique - Silva
Size and Reach - Silva
Power - Silva
Speed - Equal (maybe)
Chin - Silva
Least amount of damage taken on average - Silva
BJJ offense - Silva (slight)
Timing - Silva (slight; Silva striking timing overcomes GSP's takedown timing)
Accuracy - Silva
Killer Instinct - Silva
Wrestling - GSP
BJJ defense - GSP (slight)
Gameplan/Strategy - GSP
Grappling - GSP (especially top control)
Age - GSP
The most important factors in this fight I think are -
1) Silva's ability to finish anywhere (at any time) and GSP inability to do the same.
2) 5 round fight which favors Silva much more so than it does GSP
3) Silva's chin and constitution (doesn't cut) and GSP lack of power. This ties in with #1.
The fact that the fight starts on the feet every round is major. The fact that even on the ground Silva causes damage (much more so than Condit) than most opponents GSP has faced, and GSP lumps up easy. The fact that Silva has a major power advantage and better ability to absorb damage. The fact that Silva is the larger guy. The fact that it could take Silva a few seconds to end the fight in any round, while it will take GSP 15 minutes minimum out of the the 25 to win.
All that points to me that Silva will dominate this fight. There is a reason GSP is so reluctant to take this fight and that is because he understands this and knows his chances of winning are slim.
"Let them see that their words can cut you, and you'll never be free of the mockery. If they want to give you a name, take it, make it your own. Then they can't hurt you with it anymore." - Tyrion Lannister