NGK 97506 Spark Plugs "2 Step Colder"Maintenance is key especially when increasing power in your bmw! These NGK Laser Iridium replacement plugs are factory standard in BMW N20 & S55 motors. They are 2 steps colder than stock N54 plugs and suggested for higher boost E85, water meth injection, and or upgraded turbocharger applications across all late model turbo BMW models. We suggest setting the gap down to 0. 020". These plugs are suggested for most turbo BMW motors including the N20,