Mitsubishi EVO X Spark Plugs ILKR8E6 (Stock Heat Range) Complete Set Of 4! These Evolution 10 stock heat range spark plugs are pre-gapped and ready to be installed in your 4B11T engine. NGK Iridium Evo X Spark Plugs are designed specifically for the performance enthusiast. NGK Iridium IX plugs offers extreme ignitability, creating improved throttle response and superior anti fouling for your Mitsubishi Evo 10. The NGK Iridium tip ensures high durability and a consistently stable spark which makes them the best choice for your Evo X engine. Iridium alloy has an extremely high melting point, perfect for today's high tech turbocharged engines.