Four figures? Very true Rich but that is assuming the buyer wants a fully restored car. This could get someone into Zs like my first car did.I think cars like this harken back to an "older era" in the UK Z (and classic car) scene - when they were worth a lot less, restoration works were way cheaper and/or carried out on a limited budget and with very questionable methods and choices employed. The aim often being to keep something on the road/get it on the road as cost-effectively as possible and so that it looked okay from a few feet away. The type of work done meant that long-term survivability without fastidious care was unlikely - hence such a vehicle now being a rot box. Given the aforementioned explosion in restoration costs and much more sophisticated ideas of what a resto should entail in detail and quality, it means that such a vehicle would require expense well beyond any insurance or resale value unless the buyer has the time and capability to do the majority of the work themselves. This affects its sale-ability as a project. Those of us who know what we are looking at will place a very low value on such a car because of the obvious extent of the work needed. Someone buying into Zs for the first time who doesn't know what they are getting into might be more inclined to dive in - and regret it later unless they have deep pockets.
Personally, I wouldn't pay above four figures for it. It will need massive bodywork restoration in just about every area of the car before you even get near anything else. I guarantee every issue you start to tackle will reveal 2-3 more in the process. The first action of any buyer should be to get on KF Vintage JDM's website and order basically every single panel Gerson makes! Because most will be required.