I had to replace my warped front rotor with a new BMW one because I couldn't get a aftermarket one from EBC (no warranty). The EBC one from the dealer had countersunk bolt holes which is not made for the F650GS twin (ABS). At the time, EBC had not started production on a replacement rotor for the twin. I recently noticed I installed the my BMW rotor backward when I was comparing my bike to my buddies F650GS. I haven't notice any difference in braking power as it is. I wonder if this can be an issue or not?