nearly remembered it
1-5-3-6-2-4 and 1-4-2-6-3-5 are most commonly used firing orders in six cylinder engines
most are the former... then take the one put it at the end and read backwards for the other one....
so it would seem this is correct "GS911 says coil #4 is the 6th in firing order? " so long as BMW used the normal firing order of a 6 pot (which I think they always did on the cars) - but cyl 6 is still 6 pots away from cyl 1 - its not the LAYOUT that's normal - sitting on the bike, left pot is cyl one, the one at the other end is cyl six, as in 1,2 ,3, 4, 5, 6 - the FIRING order is which goes pop in what order