JUst thought I would add a post, my Defender had recently began running poorly, stalling, bogging etc. I expect these issues accured 3/5 times I drove it. I had a newish <10k miles GENUINE rotor button, appeared to be uncompromised. I swapped it with the powerspark red rotor button and it hasn't misbehaved in almost 200 miles, will absolutely order more of these to keep in all of the Lucas 35D trucks. I will say the truck idles smoother and throttle response has improved. May also coincide with being driven quite a bit over the last week, AMSOIL power foam treatment, and a couple tanks of V-Power. These trucks really dont like to sit, GET A POWERSPARK ROTOR BUTTON