Bavarian,
All good points, and well demonstrated with our reputable restoration shops, about the cost of restoration. Keep in mind though that classic cars, e9's in particular, may not provide a 1 to 1 yield of selling price to restoration costs.
The beauty of the e9 is unquestioned, but for several reasons, the classic car market has only recently begun to value our cars. Most e9 sales are not reflected in publications, as they happen privately.
The best scenario for resale, likely comes from a market of folks who are 1) already pre-disposed to wanting an e9, 2) those who understand the costs of restoration and 3) those who value the process of your particular restoration and car history.
It behooves all buyers, to perform pre-sale due diligence.
Yet, also know that this forum has been notorious, paradoxically so, for shooting down the 'asked for" prices of e9's that come to market. In some ways, this also contributes to the unrealistic gap between restoration prices and "perceived appropriate" asking prices.
Good luck with your sale. For the right buyer, it could be worth every penny....