We were persistent and after calling and asking for the head of tech and explaining to him what the #6 plugs looked like after running them at high boost levels, we were informed that the Iridium plug was very close to the stock length and the difference in length would not be anywhere near as important as running the proper heat range as the power levels went up. Because the stock plugs were reading so hot, We needed another solution and tried the Iridium and they are all that and a bag of chips ;-)