I think you can go here and see a pic of the painted back seats:
http://static.flickr.com/11/90443009_7d05a922d2.jpg?v=0
I was wrong, I looked on Porsche's model customizing site and it is a Porsche Option, not a Recaro seat. I forgot to note the price. In that pic the backs are, I think, fiberglass and painted Artic Silver like the car but they come in any body color I think. Notice the crest in the rear.
A must have for cabriolets especially.
You could proabbly have a custom upholstry shop cut in some professional looking harness holes. Now that would be orgasmic.