I thought this might be mildly interesting for a few people here so I'm posting these images.
These are my "Genuine BMW" pads and rotors for my 128i after about 40K miles. I did probably 6-8 autocross days (~70 runs @ 50s-60s each) and Tail of the Dragon once. No track days. After the Tail, the brakes were smoking visibly and that was quite early in their life.
I absolutely destroyed the fronts. The rotors are insanely grooved and the pads are cracked down the middle. The wear wasn't bad. They're probably 50% through their useful thickness.
Anyway, thought it was interesting. Let's just conclude that stock pads and rotors are not suitable for even highly spirited driving on the street much less autocross and definitely not HPDE/trackday.
