The BMR4A are the same as Champion CJ8 so they will fit Victor mowers and early BS and many chainsaws and more.
and the BR8EVX can be used where you would use a NGK B8EV, B8EGV or NGK BR8EV.
Hope this was some help. I'm not 100% sure about the resistor plugs. I believe the internal resistor is there to suppress ignition noise and to help guard engine management systems
from interference that may cause damage to them. So you should use resistor plugs when called for by the manufacturer but it's ok to use them when not called for.
