Since it's a not-uncommon plug swap to install NGK iridium plugs in these cars... And since it's a popular move to go with the hotter "6" heat range plugs to prevent fouling in largely city-driven cars (is this necessary with iridium plugs?)... It should be noted that the (sometimes cheaper) NGK BPR6EIX-11 (#3903) is NOT useable on our cars, so you have to stick with the BPR6EIX (#6637). It turns out the -11 (indicating pre-gapping to a larger, 1.1mm gap) doesn't have the removeable cap that's needed for our spark plug extenders. The devil's in the details.......
