Overeem. He's the Juggernaut bitch! He's ALL upperbody, and i guarantee he'll be like a turtle if you get him on his back.
Alistair is a competent grappler. He won the european ADCC's in 2005, tapping all of his opponents. Your guarantee doesn't mean a whole lot to me, it's not like he has chicken legs and no sprawl or guard.
But regarding the roids, I think it's a bad idea to let fighters compete when they are testing hot. It would become an arms race to see who can stack the most PED's in order to stay competitive and will inevitably result in health risks.
Everybody good, plenty of slaves for my robot colony?