Styling Garage was founded in 1979 by Ralph Engel and Christian Hahn in Pinneberg Germany. At the time SGS, as it was known, was sort of the Iron Chef of specialty auto builders, taking already noteworthy cars and making them totally audacious. One of the ways they did that was by converting damn-near everything leaving the factory to have doors fashioned after a seagull's upper limbs.
This 1983 500SEC is apparently just such a subject of the company's work, and is one of only about 75 cars so converted. These were often built for Saudi princes, owing to that group's proclivity for having metric tons of spending cash and a taste for the extreme when it came to their cars. The seller sort of claims that this one's a 1000SGS, but there are no rear end shots to confirm the car being actually badged as such.