i bought a spark plug feeler gauge that was in millimeters. set them all to 0.8 fitted them, and away i went. if you disconnect the battery before fitting, your engine wont need to learn the new characteristics of the plugs "according to the pulstar instructions". if you dont then it says that it will take around a full tank of fuel to get the full benefit. i can definatly feel a difference

. i think my exhaust note has changed slightly also.