More like $8k, but that's still a hell of a lot for a ceramic brake system that less than 1% of the population is good enough to notice a difference and be able to get anything out of.
Edit: I need to learn how to read. I didn't realize you were talking about the GT. The ceramic system for the Boxter and the 911 is about $8k, no idea about the GT though. Also, if you can afford to buy the GT, you're either a great driver or simply have more dollars than sense, so maybe he would notice the difference between the brakes.