I have a 2008 X-5 (sport suspension, 19", all season tires.)

Over the years (too many!) I have owned a number of 4 wheel drive and all wheel drive vehicles. Without question the x-drive is the best of the lot (at least among those I have owned & driven.) It is my understanding that the Audi Quattro system is superior, however I have never owned an Audi so I really cannot say. I can say that the amount of traction & control demonstrated by the X-5 equipped with all season tread is outstanding. I am confident it would be even better with winter tires. As I am sure you know performance tires are a much different story & are not suited for winter driving even with the X-drive.

I live in the mid-west & my daughter attends a university in the upper mid-west so in the winter I frequently drive in fairly extreme snow & ice conditions over long distances in often poor road conditions. I have never had any issue with my x-5 relative to extreme loss of traction or control. I have a fairly 'heavy foot' and tend to drive that way even in inclement weather. The x-drive system has never let me down.

Your experience may differ, driving on snowy, icy mountain roads is a more severe test, however I think the X-drive would do better than most under these conditions as well.

Hope this helps...

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2008 4.8i Mineral Green Metallic Sports Package, Technology Package, Cold Weather Package, Rear Climate Package, Premium Package, Premium Sound with iPod adaptor & Sirius Radio, Auto Tailgate, Head up display