I wasn't able to connect the BlackBox and keep the Mopar ECU in the system aswell.
The BlackBox allows for plenty ways of connecting into a car's ignition system but I couldn't figure out quickly how to 'trigger' the Mopar ECU by using the BlackBox.

As this is my daily driver, I wanted to either get it running better than yesterday, or I would go back to the stock ignition system and play with the BlackBox on another car someday.
I decided to use a GM module as a simple trigger unit which seemed to work better than connecting the BlackBox directly to the coil.





All in all, after an afternoon of rewiring and driving around a bit to come up with a better tune, I can say the system seems to work nicely.
To this point I've only focussed on the most used area of the timing map (upper left / Idling and cruising) and will try to fine tune the other areas later on.

For my engine and fuel (propane LPG, 8.6:1cr, 2-bbl 318), this is the preliminary timing map I've come up with today which feels OK to drive around with. Only at the mid/higher rpm's (3000+) the engine seems to want to skip and miss at times.