I've been researching same questions. I'm really wanting to run the stock hellcat auto.
Might as well get low mileage engine and trans combo and know its converter is set up correctly.
Figuring the swap will be around 6-8k over the engine trans price and some fab work.
Assuming new
Fuel system,
Headers
Oil pan
Wiring&ecm
Engine Mounts
Exhaust
Radiator
Coolers