I just finished replacing my stock plugs which I thought were AC's as per the owner's manual spec-but to my surprise they were denso's. the Gaps were pretty consistent between .058-.060. I put in a set of NGK TR55's gapped at a tight .055. The install took about an hour. I should have replaced the stock wires while i was in there-they look pretty wimpy for such a awesome motor. I'll order the taylor's next week before i go to the track to see if I can improve my numbers.