What top level fighters has he fought outside of his weight class? Here's a hint: it's lower than one. Silva is already a giant at the weight he fights at. Silva isn't even the best p4p fighter in the UFC, let alone in the world.
Who do you think the top P4P fighter is?
Don't say Fedor because by your definition he can't be because he's only fought HW's and fighting a MW doesn't count for much.