Hard to value as no two are the same! Some of it comes down to equipment fitted and of course its provenance. A nice swb will cost £100k and upwards
Once restored to the correct handmade standards there is a market for them. Automobiles of this class and style simply cannot be bought new and the people that have them rarely part with them.
40k seems cheap. I know a guy who imported one from the States and flogged it at Essen at well more than double the asking price of the above. And I know of another guy who's been looking for the 'right' one for several years. I think spec, history etc play really major role on pricing.
I'll have mine as a short SWB,with two doors please...
Looks good, from a distance. Just something about it screams hidden problems. Although in reality all W100's probably should. Steamed up instruments is not a good start.