Correct ballast resistor

The specs are hot actually they will never test proper out of the box. FSM has the testing temp usually 80 or so. Testng combos on different ECU's Resistance should be matched to have the optimum output and cooler ecu operating temperatures.
hence where does the coil get its ground from? The ecu of course one reason guys running .25 ohm resistors on chrome boxes burn them up on the street and if they run say .8 ohm they run forever but will never hit 10K rpm like they should it is a trade off really. Go with the manufacturers recommendation on the aftermarket coils.