In 450 Tobi told Kisame to go after the 8 tails, so it it comes to it, what do you think will happen? who would/will win?

And before anyone says 8 tails will easily win lets not underestimate Kisame. He captured the 4 tails single handedly, and if he was to be killed by KillerBee that would rule out a possible mtach up between Kisame and Suigetsu which looks likely