I would second that about the OS P3 plugs. After reading an earlier page on this thread, I was reluctant to try anything other than the GRP plug, but I gave the OS P3 a try and it works great. I don't have any sealing problems, and it seems to run better all around, from idle all the way up to WOT. I have also run about half a gallon through it and haven't had to change the plug. Tuning was never really a problem, but hasn't become one either with the use of this plug.