Its an exciting match-up, but I doubt Diaz will look good against someone who chooses not to brawl with him.
The only thing Diaz has is a good offense when someone's back is against the cage, good height and size, a good chin and good recovery from being hurt.
If GSP can keep the fight in the middle of the octagon, or take Diaz down, there may not be anything Nick can do.. GSP could pick Diaz apart with his jab, and keep him guessing with his wrestling and takedowns.
I don't see Diaz winning this..
Hard work is the only real PED.