BMW rotors are not designed to be turned. They are considered a sacrificial part of the braking performance just as are the pads.

Other than bigger brakes, it makes it much harder to decrease stopping distance with aftermarket combinations. Like many here I have aftermarket pads and rotors. And like many it seems like my choice is better than stock but my bet is none of us have any reliable proof other than the brake version of the butt dyno. All I know for sure is I like the look of the rotors, dust is minimal and I haven't hit anything.

I have never seen a comparison of braking 'packages' for any BMW. I don't recall seeing anything even comparing distance and fade of big brake packages and stock brakes.

__________________
X5 4.6 2002 Black Sap, Black interior. 2013 X5M Melbourne Red, Bamboo interior
Dallas