I think you just have to play it by ear. You just don't know what the weathers going to be like a week from today let alone a month. The two weeks before mine arrived on Dec 10th, we had that cold snap. Coldest winter in 100 years, odds on for a white Christmas etc etc. Look at it now, mild and chucking it down.
I've definitely noticed the difference in the dry with winters. I was actually getting car sick because of the feeling I got in my stomach when I planted my foot from stationary on 19's. Now, I cant get that same feeling on these winter 18's.
Imagine all the ice if the temperature did drop now.
330D M Sport Estoril Blue 19" + M Sport Brakes, Adaptive Suspension, HK Sound, HUD, Stop+Go, Vis Pack, New Pro Nav.