I know this is an ancient thread, but I was looking for the plugs on Google and this page comes up on BR9ECM search.

I found the BR9ECS plug and wondering if anyone had used them, the only difference is the electrode and form description not very clear what it is

from NGK:

CM: Compact type, low angle ground electrode

vs

C: Low Angle Ground Electrode
S: Standard 2.5mmø center electrode

I guess my question is: What size is center electrode on BR9ECM plug? I can get a BR9ECS relatively cheap, and also they do not list BR9ECM plug, listing goes from BR8ECM to BR9ECS and BR10ECS

Thanks!