I'm running 215/50-17 as my winter setup - gives me the extra inch of ground clearance. But you notice when driving that the wheels are bigger - it's basically making every gear higher. No way in hell I'd go 55. Odo/Speedo is off by a few %.
One thing I did notice is that the slush/ice does get caught between the tire and the fender. Not a ton of room there. I will probably go back to stock size next set.