I know for sure it is available on the 4.8. Also, it has a low fuel consumption and runs off the optional secondary battery.

The entire kit is BMW original, but the ThermoCall is manufactured by Webasto.

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2011 ///X5 M (On Order)

2009 X5 4.8 M Sport Space Gray/Black Fully Loaded

2007 GMC Yukon XL Denali Loaded and Customised