I would call gearvendors about the correct adapter before you buy the used unit.
I have heard that GV wants something like $600 or $700 bucks for the mopar adapter with your old ford/chevy one as a trade in.

Can anyone confirm this ?

EDIT: Straight from the GearVendors website, in responce to customer asking about swapping his unit from one model trans to another.

"In most cases it is in the 700 dollar neighborhood to switch these components to the new application you need"