I think this question has been beat to death on the tech forum. Let me tell you this from first hand experience, I didn't know any better after recently purchasing my 300E, I put in platnum 4's. The performance after the first week was just fine, but then I noticed the car was back to it's old pre-tune up days. I pulled the plugs and they looked HORRIBLE! Even the gapping was off, and they came pre-gapped. The reason? The techies will attest, the pin in the platnum plug is very small and narrow. Look at the diagram at your local auto store. They recommended the Bosch Suppers - copper core plugs. The copper core is very wide, about a 1/4". Wider spark means better spark in these older engines. I put in some suppers, tourqed to the proper specs, and she runs like a dream. Dont wast your money on them. I have them in my BMW, and they work fine. But not for the older MZB's. Thats my dos centavos.