4x4 reliability and Winter/Snow tyres

Is either of 2007 BMW X3 3.0d and 2006 ML320CDI likely to be appreciably more reliable than the other?
For driving one of the above on road in bad winter weather and snow, should I use winter tyres or M&S tyres? Vehicle will not be used offroad.

Asked on 16 July 2012 by Ian

Answered by Honest John
Can't say which will be more reliable. Can say yes you definitely need winter tyres (not all weather tyres) for severe conditions.
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