Back to your original thought, besides body work (which if you are a Fox guy you know where they rust) it will depend on just how top-notch you want the car. A lot of little things (manual mirror adjuster dust boots, tail light rubber boots, GOOD quality dash pads for 83-86 cars........) will make it a bit tough to get the car in excellent shape. Also, things like the butyl gaskets for the tail light hardware (acts as a gasket to seal the studs from the interior of the trunk) and quarter window hardware are not available, but can be made from butyl rope (available at most body/paint supply houses). Little clips and fasteners aren't available either, so get as complete and well cared-for example as possible. If you need any of these little parts, salvage yards are a good source for these parts.