starting my 2015 vvt hemi journey

In my opinion I would use the Hotwire harness. Mainly because that is what I have had on my 5.7/545 for 12 years now. The ECM can be gotten from a salvage yard for under $100. I don’t know about later model ECMs (mine is a 2005) and the truck ECMs are not locked. Call Hotwire they will be able to tell you. I guarantee their tech support is better to deal with.