I have every bolt on part for the SHO including Meth injection. I purchased the motocraft plugs gapped at .030, and when spraying meth, it seems to be loosing spark, so I am having vehicle picked up by Livernois and transported to their facitlity to put new plugs in and tighten the gap, and dyno tune the meth kit. I would def. recommend putting the gap at .028. You may lose some MPG..... but the performance is what will improve.