Never used them, but I checked out the link.

Usual qualifications about any dimples, drilled holes, or slots taking away strength from the rotor, and contributing to brake noise.

Note that in all of their detailed descriptions of their four styles of rotors, they never once mention the cooling fins. That is a flag that goes up for me, indicating that they are likely using cheap blanks with straight fins. The design of those fins is not likely to be the same as OE, which compromises performance.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue