Lol I have been following this thread for some time.
All I can say is each person has its own taste. Yes I agree the AWD version will be more safe and easy to drive in wet and slippery conditions. If that's what you are looking for in a car, than go for it. But maybe if you are concerned about safety so much, don't buy a 320HP car? For the weather in Belgium you certainly dont need an AWD car. As you state yourself you spend most time in traffic jams like most of us.
For me personaly when it's wet and slippery I don't push the car to it's limits at high speeds on public roads. Maybe have some low speed fun at roundabouts when nobody else is around but thats about it. I enjoy driving a lot more in dry and 15+ degrees temperatures. And thats when I enjoy the car the most. FYI I bought the RWD version of this car.
As for the person that did the testdrive... The only winter tires available in the same tiresize as the original wheels are the pirelli sottozero runflat. Run flat tires make the car feel a lot harder. Also out of personal experience I can say they have a lot less grip than regular winter tyres. But to be honest, besides if there is snow I get around nice and safe with the summer tires as well. On snowed roads that's where they make the most difference. Hence I am currently running the car with 225/40/18 michelin pilot alpin a4's winter setup on the original wheels. I have a nice summer set ready with the original tyres
Also with the roads being full of salt and with the low temperatures of the last 2 weeks offcourse grip levels are far less. But if you play around with the throttle and the ESP partially off you can get away pretty quick without being dangerous at all. Comparing with a chipped 2.0l VW Scirocco it even spun the wheels in 4th gear on the highway doing 160. So I dont need to mention how bad grip was in 1st/2nd/3rd gear with this car. Not so with the M135i. It pulls away very quickly from stand still. I guess you just need to dose the gaspedal a bit.
And Koen if you really like the X-Drive version of the car, all I can say is go ahead and buy it. I am sure it's a pretty good ride. Its about personal preference. But no need to convince other people that prefer RWD over AWD that the X-Drive is the better car. Nor won't I come here to say the X-Drive sucks and the RWD owns :-)
To each his own I say. And I am very happy with the RWD version even in the rainy country