This question pops up a lot, so I'm just curious what plugs the N55 guys are using. It is my understanding that the same plugs work across the N54, N55, S55 engines.
SILZKBR8D8S is the BMW N20 plug which is 1 step colder and seems to a popular choice.
SILZKBR9F8S is the BMW N20 Flex Fuel plug and is 2 steps colder
SILZKBR8D8S is the BMW N20 plug which is 1 step colder and seems to a popular choice.
SILZKBR9F8S is the BMW N20 Flex Fuel plug and is 2 steps colder