I understand that 22 is colder for Motorcraft than 32. I have the 22's in the motor right now for that reason. Well, that and they are double plats.
Until I see a case of someone running a street car that has the same "backwards wasted spark" ignition system (if I understand how it works correctly) reporting back good experience with a non-double platinum plug over a significant number of miles, I'm sticking with double plat for now. I'm a guinea pig on enough things with this motor that I just don't want to throw one more unknown into the engine. I did try the NGK TR6 plugs to see if going colder would help my timing issues (and might throw them back in for a week or two soon to check again now that I find myself pinging a little), but I don't plan on running 30,000 miles on them (as they aren't double plats).
I'm more interested in the experience of people who drive their car every day to every place they go than what racers think, to be honest. Racers have a different priority set than I do. I bet if I changed plugs every 500 - 1000 miles (or after 10 1/4 mile passes) those endorsements of Iridiums would be fine.
Not bagging on you - just stating my point of view. Heck, I like the fact that you try new things. (This coming from a guy that went from a bone stock motor and never coming on these boards to putting his order in for a 3L block over the course of 5 days last summer.) I just have to pick and choose my battles so I don't get buried in tracking variables so I can determine what works for me and what doesn't.
More power to ya! Aloha.
