Jason Cammisa (Hagerty) did a very good video on the 500E. You might appreciate it.Indeed.
Originally only 500 made probably to homologate the 32 valve V8 for Le Mans (It was fitted to the MB supported Saubers and their youn star driver line up) though it sold well enough for 1000 facelift models to be made later.
MB didn't have a suitable production line for the volume or, at that time, a development department for such a car. so it was entirely sub-contracted to Porsche.
There are around 1000 mods to get the engine into the 124 shell and even the seats and carpets are unique to the car.
I bought mine via the F1 VIP programme and picked it up from the factory so I have owned it 30 years now.
Michael Schumacher has driven it