This is the crux of it, the dealer says the car is rare and I agree you do not see very many especially in great shape (at least not in my area) but I don't believe this model is a collector. That said, my expertise is nil and I do not know what kind of production Mercedes had on these cars. I may be wrong and they may very well have been a limited run. If they weren't then Blue Book is taking into account the nice condition and he is $1900 too high.