Anyone using stock ECM and harness?

Just a FYI, probably not useful for you, but i use the 2015 6.4 SRT including a few of the OEM control modules (BCM, RF Hub, start button) and the hacked up original harness.
What i can tell you is, that if you use the original harness, book some time over at techauthority.com in case you need access to the wiring diagrams.