When I worked the back service counter at the dealer, we would get cars in for service with Bosch plugs from the factory. This was going back to E39, E38, E53 chassis era. At that time the ETK gave the parts team both options of NGK or Bosch (it still does actually). We would just ask the tech what he pulled out and gave the replacement for the same plug brand. Over time, people just started requesting NGK over the Bosch.

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E70 LCI 35D

E90 LCI 328i xDrive
E39 '00 528i Sport/5sp
E28 '88 535is
E84 35ix M packaged
E38 '01 740i Sport
E39 '02 M5