From what I can figure out the NGK BCP5ES has a 5/8" hex, according to the NGK spec page - not sure what that means about the size of the BP5ES.
I mentioned in my previous post purchasing wires from Kingsborne - these would be around $130. I found these Bosch wires on Amazon for half of that -
http://www.amazon.com/Bosch-09146-Premium-Spark-Plug/dp/B000BYB3E2/ref=au_pf_ss_1?ie=UTF8&Model=300CE|779&n=15684181&s=automotive&Make=Mercedes-Benz|63&Year=1991|1991&carId=032
The specs mention a stainless steel Mag winding....and nothing about a copper core - which I read about numerous times in other threads.
What do you think?
ryan