Here's a link as a follow on to this discussion: https://xoutpost.com/bmw-sav-forums/...ium-plugs.html

Pulled iridium plugs after 36000 miles and the gap had opened up .020"+ and the electrodes were melted. Some suggested they were fake as I purchased from Amazon. Maybe. I don't know. I'm going to purchase a new set from Rockauto.com assuming they have a higher probability of not being fake and see what happens. If they were it could be why my mileage went down when I installed them.