I have owned my 2006 Cayenne S since new. Last spring, I started loosing a small amount of coolant, no drips, just missing fluid. That was the trigger to get the coolant pipes replaced before more damage done. The total bill was about $2400 from my Porsche dealer here in Atlanta. The vehicle had about 85,000 mikes on the odometer at the time. I believe about $700 dollars was picked up by the settlement and I paid for the remainder out of pocket. At least I know now that my Cayenne has the aluminum coolant pipes in place. No issues since.