RACING SPARK PLUG FOR M50/M52/M54 ENGINES These spark plugs are recommended by BMW Motorsport for use in their DTC racing engines. We find a slight horsepower increase and greatly increased durability over the OEM road car spark plugs in competition use. We attribute the improvements to the fact that these spark plugs are designed for the high temperatures and cylinder pressures encountered in a racing engine. These spark plugs are a direct replacement and come pre-gapped just like the factory road car plugs. Please note: these plugs are not for the S54 engine in the E46 M3, MZ3, or Z4 M Show More Show Less
