Convert Mercedes 320 from sedan to streamlined sedan

Sorry for putting the post here but there is no forum for W142 / 320.
There is a 320 sedan for sale (like this one)
for relatively cheap (30000€), that I might buy even though it needs interior redone and has no sound system, if it is still for sale when I have the money. I always loved the 540K Autobahnkurier, and I saw that the 320 had a version called Streamlined sedan:
From what I see only the rear end different. Do you think it would be possible to transform normal sedan to streamline sedan? How much body shop take? Would it be worth it? At the same time, I doubt because car would not be fully original in the end...
Thanks







