but it's challenging. Riveting is the least of the concerns.

A kit (even the Factory Five, which is one of the oldest and most refined) doesn't have the level of engineering in it that any mainstream car you've worked on does. Not even close. Plenty of stuff doesn't go together the way you think it should. And you don't get the benefit of seeing how everything came apart. Plus the drivetrain is wide open, so depending on the choice there, you may not have much guidance with how to make that rather critical stuff work. And beyond drivetrain, there's leeway in many places to do things multiple ways (there's actually a decent aftermarket for FF). The bonus with FF is that because it's been around so long and been successful, there's a big, extremely helpful online community.