Hi Etienne and welcome!

I've been searching high and low as long as my flu-ridden head permits, but I cannot find a pic of a Dax of a friend of mine. He has a carbon and ridiculously high priced Japanese exhaust pipe. I cannot really tell whether it gets warm or not, it probably greatly depends on the style of driving, as in high engine demand produces a high temp muffler. So it is possible, but I have no clue about the temperature. You could try to send him a "PM" by
clicking here. I'm sure he is willing to provide you a good answer! (if his email address is still valid >.>)