Well I picked up a new (well with 200 kms on it) 2011 X5 35d drove 1600 kms under extreme winter conditions from -20 to -40 degrees celcius.....it is so cold that when I fuel up the hose on the pump breaks off, at -40 it takes a while for the engine to warm up drove for about half
an hour before the engine warms up enough to have warm air inside the truck.. I think the key is to block the kidneys with something so it'll stop the cold air from cooling the engine at a fast rate....so for those people who are wondering the reliability of this truck at extreme temperature....well I might say that I am really impress of how well the engine performed......just my 2 cents