In theory, yes it should. TB2's performance is almost entirely dependent on the gpu, I've considered this myself and talked to our engineers who told me that it SLI should provide a performance boost, however we haven't really tested it. If you do, we will be very curious to know how well it works for you.
update 2: Fleshed out the robotic guts: Each wheel has its own robotic arm. Also each pair of wheels gets its own engine. I want the outside shell to look sleek with some wear n tear. In contrast the interior guts are going to be highly detailed and grunged up. I can't wait to dDo this bitch!