I am about to perform first Spark Plug change on my 2015 GLK350 (276 Engine), and purchased OEM MB Plugs from the dealer, as well as BOSCH ZR6SII3320 [OE Fine Wire Double Iridium; Pre-Set Gap: 0.027" (0.7mm)] from RockAuto.
The gap, and the overall electrode geometry look very different between the two sets of plugs, and although I understand the Bosch are Double Iridium type, I wondered if anyone here had any experience with these alternate to OEM Spark Plugs?

I am also replacing the coils with BOSCH branded coils (Coil 5 of the factory installed coils has failed).
Thank you

 

<!--td {border: 1px solid #cccccc;}br {mso-data-placement:same-cell;}-->They should be simple to access and replace as a service part. There should be no need for any specialized equipment. Find a Torx bit kit; sometimes, a normal plug socket will suffice. If not, utilize an existing socket set as a guide to find the appropriate one. I can't say about the cables, but they should easily pop right off. I had to remove the intake manifold on my previous car to get to the spark plugs from https://www.scrooz.com.au/fasteners/wall-plugs/, which required a new gasket. Maybe not for a mechanic, but it's frightening for the typical home gamer trying to undertake routine maintenance.