I fitted mine the first day. Easy to fit - just prise the pins out with a small screwdriver and then pull them all the way out. Remove the inserts and re-fit through the new mudflap, pushing the pins home firmly.
Removed them on the second day. Rubbish for anything other than driving on a level road. They scraped on every bump and bend and were worse with a passenger in the car. Not quite sure why Tesla would supply these in this form.
Looking at aftermarket ones as I think the car could do with them, but they need to be practical.