I think the non resister Bosch plugs run about .90 cents each. Just buy a set and see if you notice a difference. It could be an interesting experiment.

Since I have a diesel I don't follow this, but I was always told to use copper non resister plugs in MB's, unless it is an M112/M113. The newer engines use the long life platinum plugs like everyone else.

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2006 CL500
2009 C300 4matic
1969 280SE
2023 Ram 1500
2007 Tiara 3200