What others above have said is correct and I think although we may have got off to a rough start here Martin I think you'll find that once you get to know this 'clicky' bunch, we're actually on your side and in most cases helpful;).
You see we are a relatively small community of enthusiasts who have been into these cars for a long time, as mentioned above. For a long time we have been told zeds will never be valuable, but we are seeing a modest surge in their values and interest in the marque in the last few years, thanks probably to video games, movies, and websites like SpeedHunters bringing this car to a new generation.
So every so often someone comes on here posts an ad that says I want X for X amount and the long term people are thinking to themselves "pick a number and get in line".
Now I don't condem anyone for looking for a bargain and $4-5k for a rolling shell is actually quite a lot of money for a car like that, when you consider what $5k can buy. So no harm in trying, but I think you'll need to be very quick or very lucky to get what you're after.
However hopefully you can prove us wrong and you'll start a build thread so we can all see your progress .
Welcome to the community.