I noticed something today. No matter how much you torque the M6 bolts and the lock rings, due to the natural torque reaction, the motor will work itself up and against the downtube. This is not a problem unless like the Trek, the rear derailluer cable runs down along there. If this cable gets pinched, shifting will become problematic. I discovered I could not shift my whole range and this was the cause. It has been corrected by loosening the bolts, moving the motor down, moving the cable to the left out of the pinch zone,and finally pushing the motor up and back against the frame down tube. Shifting is now normal.