Dack, seriously, why do you keep spreading fear about spark plugs not purchased from dealership? There are tons of people using plugs sourced from plenty other places with no problems. You keep spreading this misinformation and have never provided any quantitative information about alleged difference. Your position is based on a handful of stories about folks who had misfires. There are equally as many stories about folks who have had misfire issues with bmw sourced plugs. The guy on page 2 of your DIY even admitted that he put the original plugs back in before he gave up and took car to dealer. Seriously, i dont mean to be a dick about it, but for the love of god please post some hard data instead of regurgitating a bunch of hearsay.