Hot ballast resistor & ICM

Have you checked the system charging/ running voltage? Maybe it's over voltage

^^ As Redfish said, so far as I know, ANY modern replacement ECU is "4 pin" whether it physically has 5 or not. In other words you should only need the single resistor

Also, if you are running a "hot" coil......high output.......it may very well and probably WILL run hotter. If you are, look up the specs and see if it requires a different resistor. Some of them require TWO.....in series, the one for the aftermarket coil, in series with the "stocker."