I have been looking real hard at the Factory 5 kits.
A buddy of mine has a 5.0 5-speed GT mustang convertible that I can buy for 2K.
So most of the doner stuff will be cheap to get it moving.
I wrecked a 86 GT ragtop, a few years back. Sold the drivetrain ,to a gent who built a Factory 5 kit. For the price, I was impressed by the kit quality. If I had the initial cash,I would do one.