As you said, "I know the rare engine option makes it difficult.", but like Alan and Jim, I think your best bet would be to replace the engine and sell it separately.
In the current market, with a standard 1915 VW engine and good marketing to the world, it will sell for $33,000.
I don't know the value of the Porsche engine, but with the Porsche engine, it could sell for as much as $40,000... if you find the right buyer! But, I think that "right" buyer would be someone who would do what we are suggesting.
Good luck.