Denso Iridium IK24 Spark Plug These 3 step colder plugs are recommended by URD if you are running the 7th Injector and 2.1 pulley upgrade on a Supercharged 5VZ engine. If you are running the stock pulley (Low Boost) on the 5vz supercharger, Magnuson...

NGK V-Power Spark Plug LFR6C-11 NGK says: “With improved ignitability and fuel economy over OE Nickel NGK Spark Plugs, V-Power is original equipment manufacturer (and racer) approved. NGK V-Power plugs feature a unique v-cut in the center...