FYI Very Interesting
Here is some URL's to check out to see the specs on these plugs. Very interesting reading.
Disclaimer. I do not represent Denso or sell Denso or endorse Denso in any way shape or form. I find this a interesting product and I would like to get other peoples input.
1987 260E Charcoal Grey 157,000 Miles
1987 260E Forest Green 120,000 Miles