+1 Correct Mike. Sort of a waste fire setup going on there. Second fire is sensed through the coils. Right after ignition the coils run 400 volts through the plugs and take readings from that. Plugs and coils will be a "maintenance" item on the M3.
Originally Posted by Mike Benvo
Not 100% sure here, but I believe this is more of a function of the coil packs and the feedback they receive from the spark plugs. So theoretically this should remain in-tact.
Supercharged cars normally have misfire detection turned off because the boost will throw the car into limp mode with it enabled.