You will want this if you live anywhere South of Brisbane, and probably if you live North of Brisneyland also.
It gets cold at 8000FT, and early mornings in the desert are no tropical paradise either. Being cold will sap your energy and enthusiasm very quickly. You already have a nice smooth engine – add cabin heating and arrive at your destination without getting hypothermia along the way.
The Viking cabin heater kit takes the warm air that has passed through the radiator and directs that through the cabin – it does not use a shroud that surrounds the hot exhaust like an air-cooled engine would use. Exhaust shroud systems are really dangerous as the slightest leak or hole in your exhaust can send poisonous gasses directly into the cabin. This cannot happen with the Viking system.