When I replaced the plugs in my E420 V8 the local parts house did not have the Bosch plugs. But did have the right ones in Delco! Well I needed plugs so I went with them figuiring if they did not work I would just replace them. Well they have been in for 6 mo. and seem to be working fine. They are non res.
I was also getting a problem with missing and total power lose . Found out if there is a misfiring the computer will shut down 4 cyls to save the cats. I put on 2 new caps and rotors and the above plugs and Bigblue has been purrin like a kitten since!! I am not trying to plug Delco just my experience with them.
Smokie