In short the answer is "it depends". Summer tires are not recommended of course, becuase BMW, like every other manufacturer, is trying to cover thier a@@. I'm sure many will disagree with me, but if you have some experience driving on snow/ice, you have an understanding on the physics of snow/ice driving, your county/municipality is good about road care and you live in a flat area, you should be OK. I drove for years and years on RWD cars with summer tires and never had an issue. Two weeks is almost nothing. All that being said, purchasing winter tires is a safer decision.

__________________
Next - M3 or M4? (f32)
Current - 2010 128i convertible (wife's car)
Previous - 2009 M-sport 335i coupe
Previous - X5 3.0i with prem/sport
Previous - 2000 ///M roadster
----------------------------
Someone should invent a sarcasm font...