Originally Posted by orthojoe

Reasons
1) they cost $17k to replace
2) they only last 6-10 track days before needing to be replaced
3) you can't run track compound pads which give better bite, stop better, and last longer than running PCCB rotors with OEM pads
4) unsprung weight is over-rated. I couldn't feel the difference after switching to iron, and my lap times dropped because I could brake harder and later with track compound pads