Just some things you will need to remember when fitting Power windows yourself
1) You will have a hole in the Door trims when you fit the power winders (No Biggie, U can get Fairmont Door trims or something).
2) You will need the Power window switch box thingie in the center console
3) You will need to run 2 High Power Cables (Stuff that can handle around 20 Amps) in to the Front Doors, and 3 High Power Cables for the Back Doors (Due to the Power Window Switch)
The Power Required for the Center console swithc box will need to be around 40 Amps, (Ford uses a Circuit breaker, just incase the motors surge more current).
The winders Basically bolt straight in to where the existing Manual winder sits, but you will need to drill out 3 Pop Rivets, (Heavy duty mothers) to remove the existing winder).
As for Fusion getting cheap parts, Yeah I dunno what his secret is, but from now on, hes is buying my Ford Parts for me, as I paid $200 For 1 Genuine Winder). The Price he got his rear window for, including fitting was a real eye opener, and the funny thing was I was there !
I dunno, maybe the guy selling the stuff was Gay, and took a fancy to him ?!?!?!?!
Hehehehe, Just joking Fusion !
P.S. Its a long job if you want to do it yourself, you will need at least a whole weekend to do all four doors, but It is not impossible, and shouldnt really cost you more than $600 for all four doors.
Front doors may be easier though, as the Console switch box, is much more common, as well as the Front Door Trims, as I believe that some Futuras, and XR models had Front Power Windows.