Greetings from Austria!
I'm on a short ski vacation with my family in Austria right now and don't have precise test figures at hand. As far as I remember, the Cayenne Turbo does 100 kph to 0 kph braking in around 39-40 meters. As soon as I get back home, I try to find more precise figures. The Cayenne brakes pretty good for it's weight (it weights around 300 kg more than the ML 55), however I find the brake feel a little bit too soft compared to my ML 55 AMG.
Don't expect wonders though: the Cayenne has good to very good SUV brakes but if you take a 996 Turbo and a Cayenne Turbo from 200 kph to 0 kph, I bet the results would be shocking. Almost 900 kg weight difference speak for itself.
So the 100 kph to 0 kph figure isn't that interesting but the 200 kph to 0 kph figure. Maybe we'll see a car magazine do such a brake testing, it would be highly interesting.