it happens everytime i drive the car hard, which is usually most of time, i do however to wait for the respective oil temps etc and then drive for a bit before i start to hammer it. its weird because after the 1st 2 quick changes from 1st to 2nd, it starts to grind, i also assumed it was the synchro's however bmw thinks otherwise. they replaced the oil, clutch and pressure plate and even the flywheel, seems to have made it worse. the only time i will get the gear in once it starts to grind, it by waiting for the revs to drop, almost like rev matching with the box