After my recent unpleasant experience I'm just going to stick with cheap champions and change them more often. I've run the Bosch Plats in my E320 and didn't notice any difference with mileage, the way the car performed, etc. etc. I had good luck with them.
I replaced them with the Bosch Supers just because so many people on this list recommended against using platinums. Oh well, I doubt you'll have any problems with them. They do have a built in resistor whereas the Supers don't. The champions I'm using have a built in resistor too, they work great too.
I would run them for a while, if your car runs great then leave them alone, if your having idle or running problems than I would try something different.