The manual states that one is supposed to use copper based anti-seize when changing spark plugs. I've heard from other sources that BMW specifically warns against using anti-seize or silicon boot grease during spark plug replacement. Is this true?
Always be careful with any compound containing silicone when working on engines with lambda oxygen sensors. The silicone will poison the sensor, requiring it to be replaced. This includes gasket adhesives and sealants, lubricants and greases that could off-gas or come in contact with air, fuel or oil used by the engine.