I'm much more of a GSP fan than a Silva fan, but I think making Silva drop to 170 is unrealistic. Meet at catchweight, and lets see if GSP's TD/ground control can counter Silvas laserbeam accurate striking
This is how I feel besides the fanhood aspect.
A catch is perfectly fair. If Anderson is so big then going 5 or 7 lbs under what he normally cuts would give GSP an advantage. GSP is already much younger.
GSP is also the wrestler. The stylistic matchup is about the most interesting out there. Anderson's weakness is wrestling, so why can't GSP wrestle him? I'd liek to see if he can. People say GSP would beat Chael...and Chael gave Anderson his toughest fight. So what is the problem?
If Anderson goes matrix and gets a crazy KO like he does to everyone else...it will have very little to do with the size difference.