There was also an article back about the year 2000 about a big closed door engine design conference between just the German Mercedes engineers, and the American Chrysler engineers.

The main thing I remember from the article is that someone was quoted as saying,
concerning the combustion effects of using twin spark plugs:

They taught us some stuff we did not know,
and we taught them stuff that they did not know,
and in the end we decided that twin plugs were indeed good.

Remember that when you are trying to get to the #8 cylinder plugs to change them.