ala, you should try using Physically Defensive Jirachi, it takes Kyurem's moves relatively comfortably, and it can break Substitutes with its Iron Head. It's a safe switch-in, at the very least.
I echo Princess Bri's sentiments that Kyurem-B has been unimpressive for me. It was not as monstrously bulky as I expected (Modest Rotom-W's Hydro Pump broke its Substitute without Rain -_-), and the current OU already has the tools to effectively check Kyurem-B. I doubt it would alter the BW2 scene as much as Garchomp did.