I took my original BMW ones off at 65K. I like to change that kind of stuff right away when I buy a new 'used' car. The plugs were in excellent shape. I used NGK to replace. cost me less than $45 and was the easiest DIY I have done, I6. I purchased before I found bmwmercedesparts.com They list BMW plugs for $13.79 each. Still pretty high considering I bough all 12 original Mercedes plugs for just under $70. Same 100k life plugs. I wonder what the diff is?
