If Porsche says 20K, then I'm sticking with that. I figure they built the car, warranty the car and they should know the car. And I don't really want to be bothered with changing it more often. I'll warm it up, drive it a little easier for maybe 500 miles, and take it in for it's scheduled services. When the warranty is up, I'll get rid of it - hoping they will have DSG transmission, more HP, and lighter weight car by then.