I have same plugs in mine. I will have to look at them. The very thin center electrode must have some deficiences in capacity due to the small size and wear faster. I have had experience with the original Bosch Plats with center insulator cracked and broken in some cases.
My worst experence with plugs like the plus 4s was when I had a Mazda rotary and used Lucus plugs that had a similar config (4 ground electrodes). The combination used up plugs in 5000 miles.
Anyone have experience with the NGK Iridium plugs?
