I came across some seats from a 07 GT earlier this year that had both power seats so to quiet down the complaints from the passenger on how low the seat is I am going to add the power seat on the passenger side.
It looks not bad until you find out the connectors are completely different from non power to power seats. Both have 16 pin connectors but are of different shape, the power seat connector has larger pins for the power and ground circuits of which is not possible on the non power seat connector. Looks like all I may have to add is a power and ground wire for the seat after I get the power seat connector soldered into the cabin harness.
To do this you require a power seat base (duh) and the cabin harness connector for the seat available from any donor Mustang, even the newer 2010 and up seem to use the same connector. This connector could not be found in the Ford parts list as a repair part so it has to come from a donor car.
I attached the 2 pin outs for both seats.
I finally got the passenger seat installed yesterday. Soldered in the connector from the donor car and had to install a ground wire and the power wire. The BEC has the power tab for fuse 15 but no output tab. I made my own tab for it and ran the power wire back (what a PITA that was). Had to remove the passenger tire and wheel well to do it. Everything worked in the end with no smoke or airbag alarms on.