The 500 SEL sold in the United States was a detuned version of the car sold to the rest of the world. Perhaps Mercedes still had some lingering anger towards the Americans left over after WWII. What else would explain selling weaker cars in the U.S. for an astronomical price. It's almost like they didn't want anyone to walk into a dealership and ask for one of these cars. They probably stored them out back under a tarp so no one could see them either.
The United States market wanted a 500 SEL, and they wanted
the real version, not some washed out, overpriced model. They found a way to get them. Nearly 22,000 of them were imported into the United States. They were unofficially called the grey market 500 SEL's. It was both a sign of American's desire for decent cars and a slap in the face to Mercedes for making little attempt to provide them with one.
These cars were technologically advanced for their time. They had a self-leveling suspension and the smoothest cruise control on the market, with no lunges or hard brakes when encountering a hill.
These cars can still be found on the used car market. I suggest using eBay to find them and parts that might be needed to repair them.