Had to comke out of forum-posting retirement for this...
I think Gonzaga would lose to Lesnar. Not saying Brock would win- but I do believe Gonzaga would lose. Even if he has the tools to actually beat Lesnar he won't use them once he gets hurt. Look at his fight against Randy and Werdum. GG basically gave up, and once he does its over.
And Mir took a pounding to the head but overcame that and didn't give up, a pounding that GG would not overcome.
I say Lesnar takes GG down, hits him repeatedly without making the mistake of hitting to the back of the head, no standup, and GG will give up mentally.
TKO win for Lesnar.