Best coil, box , resister combo ?
One huge "modern" problem is quality of parts
I gave up on Mopar ECUs I just went to a simple, lo buck HEI module fired by the Mopar distributor and driving a stock coil.
You don't need a ballast, and they will drive a wide variety of coils. Even with a Mopar factory coil, the HEI module produces more fire than a stock Mopar ECU
I don't even use a heat sink. Just mounted it to a flat on the firewall by the dist. which had already been drilled by someone mounting a conversion system