There is no point in the X5, Toureg, or Cayanne having a transfer case. None are designed for serious off roading. For snow use, you don't want to run in low range, as generally you want to reduce the amount of torque to wheels when you start out, not increase it. The only time you run in low range in the snow is when cutting trails in 3+ feet of snow, and usually then you winching yourself half the time.