On our '66 Newport, after we got the car (back in early 1966 after the new 1967 Chryslers had arrived), I was looking around to see what it was. I found ONE extra wire and connector sneaking out of between the overlap between the front carpet and rear carpet sections, under the front seat. Our car did not have a factory power seat, so we figured it was a wire for a power seat that our car did not have.
IF that is accurate, which a investigation for wire color would indicate in the Chrysler Factory Service Manual electrical schematics, then that would be your power wire to use for one or both of the BMW seats. Once connected, that ONE wire would power the electric motors of the seat tracks. Might need to verify the connector positions on the BMW seats to determine if they are self-grounding or not. If not, then an extra ground wire would need to happen.
Considering how narrow those BMW seats are compared to normal Chrysler bucket seats, what is going between them over the transmission hump? Just curious.
Just some thoughts,
CBODY67