As much as I hate the red-neck Silvia, he would destroy Lesnar. Size advantage for Lesanr would not be a factor and Tim is waaaay more experienced in all aspects of mma. Even if Lesanr took him down, Tim would get right back up or submit him. More than likely, it would be 3 rounds of Lesnar getting pummled from the outside and looking like Monson did after fighting with the "Mainiac".