However, you are not dealing with Ryan, and your interest is specifically realated to the 718 shell. From my post, you may recall that the shell was about the only thing I felt significantly worthwhile to keep. Make sure the shell you are looking at includes the doors, and the side grills.
The shell was actually made in GP Spyder moulds and laid up in Mexico. So Ryan couldn't screw it up too much. Still, don't expect the doors to fit, or the side grills for that matter. And, I seem to recall that one front wheel arch is a little further back on one side. The car is somewhat slab-sided by design, and the individual shapes of each of the major pieces (front, door, rear) tends to wander around in relation to the piece next to it. In other words it looks like 3 different pieces rather than one continuous shape.
Plan on quite a bit of body panel fairing.
In summary, don't expect it to be "perfected" as the more numerous versions of speedsters, 550s and Cobras. Still, it is within range some perfection by youself if you want to invest the time. And considering the overall time you will invest in the project, the fiberglass work will be relatively minor and comparatively easy.
As far as how much to pay? It's kinda like how bad do you want it? Most don't realize the size and scope of the project. Just having a body is about 10% of it.