Year and model?????

Most Mercedes REQUIRE non-resistor plugs for proper ignition system operation and using resistor plugs can cause idle roughness and high emissions, both due to misfires - maybe not when the plugs are new, but just wait a few thousand miles!

Go to Fastlane and order the correct Bosch spark plugs for your car. You'll have them next week, and you won't have to run all over town looking for them. Most auto parts stores DO NOT carry the proper Bosch non-resistor plugs for Mercedes and often cannot even order them.

Duke