The D8ea is the current version. The D8RES-L is a resistor plug but with a longer snout that gets a little further into the chamber. I have learned that these coils are super low resistance in their ohms. I wired in some 25 watt 2 ohm resistors before the coils. That helped. Then I added the resistor plugs and all is right with the bikes ignition system. Basically, converting the coils from 2 ohm each to 4 ohm, and then adding more at the plugs to replace what is lost in the old plug caps. The math might not add up to the same but my bike likes it.