Need to replace the front seat upholstery. There are huge price differences from $430 to over $1100.
That expense depends on your goal. For a daily driver you want durability. For judging you want quality. I usually went for the quality.
The price differences seem to be for different styles, standard vs deluxe. Do a review of what and where you got prices.
Do I need the foam with or without listing wires? That's another $100 per seat from TMI.
I reupholstered well over a dozen sets (I use my grandfather's 100 year old plus upholstery tools). I found out the hard way. Replace the foam. The wires usually rust away, so think about getting another Ford seat to use for "parts".
To be truthful, I would order from NPD.
Jim
A lot (yes, it is two words) of the techniques are documented in the "1970 Mustang Interior Assembly Manual" (AM0032).