I just thought you guys, 1M owners, would appreciate how the spark plugs look like in my 1M's engine after just 17300 miles (~ 28000 km) - the car is my DD. I had them replaced at my second oil change per BMW's maintenance schedule. You can see that the threads were oil wet or had some oil residue (they all looked more or less the same) and I also found a tiny bit of oil at the bottom of the spark plug wells. As for the tips, they all looked ok:
