I would suggest using the standard copper core bosch plugs for your car.
Platinum plugs may help other cars, but most have found they don't do much in a benz.
I have standard copper core plugs in my 300ce, my brother uses standard copper core plugs in his range rover instead of those +4 plugs, and his car runs much better now than it did with the +4 plugs that have the 4 arms over the electrode.
Check fastlane or partsshop. you should easily find the right standard plugs in there for your car.
'92 300CE - Sold
2004 C240 - C7 Wheels
2015 ML350 - P1, Pano, Ash poplar wood, Sport Dinamica interior, Running Boards Keyless go.