We have used them on several race application, and the only problems we had are ground issues (like Wrenchbender said). On a new or rebuilt dist. they are painted which does not make a good ground. We ran a wire from the bottom plate, where the module (points) mounts to and external ground (allow for dist. advance).
Petronix works better without the resistor. We have never ran one with a resistor.
Hope this helps
Steve
