[lkchris]

I think this first appeared on the 2005 Mercedes SLK if not on earlier SLs. Not sure about BMW.

In any event, it requires an electric heating element and a blower and ducting all contained within the seat.

Porsche seats are a lot more lightweight than the seats in the others and there would seem little room for these components.

I wonder whether these have been offered for later Porsches.