I'm going to admit it now, every once in a while I go off on the new stuff that comes out, when the split fire plugs came out, had to have em, know what they were junk. I have run the bosh plugs you describe in my 960 for years and they are good plugs. Now with that said, I have gone off again, this time it's the E3 spark plug, bought them from J.C. Whitney--only sorce for them right now. Put these little jewels on the car and ya know what , they have done everything they said they would on their website, Smoothest burn I have ever seen, turn the key and the engine jumps to life, after 3k on them when like siting at a stop light and you get that occasional bump of a slight missfire, thats no more,if you did'nt know the engine was running you couldn't tell if you in the passengers seat and almost like that in the drivers seat.
I'm going off again on this product and order a set for my 5 series BMW, with that said check out the E3 Spark Plug website and decide for yourselves.
Good Luck
Poolman