Originally Posted by kiwi29
With all of this spark plug talk for n52s, how much of this revolves around n51s?
Depends on your N51 manufacturing date. Up to 3/2009 an earlier coil was used, after that the latest part (BOSCH 12137594937.) Refer to this RealOEM page:
If you have a car with a 3/2009 or later build date, use the latest NGK LZFR6AP11GS plug.
Earlier cars, replacement coils will need to be the later 937 part, and use NGK PLZFR6A11S plugs until all the coils have been replaced with the latest part.