Alright, let's dig deeper ...
At the BMW Museum in Munich, this car was once described as a "BMW 332" from 1939 :
http://www.bmwpower.lv/files/member_galleries/576/5798/500/1254827693_21193.jpgBut on the museum's picture, the car is slightly different : the door handles are slim and located just below the side windows, and both doors are "suicide" ones.
Then I've found the car you've posted on the official "BMW Classic" website, still described as a "BMW 332 Protoyp", like on this picture :
http://bmw-grouparchiv.de/1/webmill.php?id=158078&foldertype=auto&foldergroup=irc&ditem=151845&dmodule=505&lin=detail&browsefolder=1398543801&t_browse=1This time, the door handles are thicker, located below the beltline and the rear door is a regular one, not a "suicide" one.
After studying the content of the "BMW Classic" website, the story of the BMW 332 is as follows :
- scale mockups, technical drawings and full-size mockup made in 1939-1940
- actual prototype (with suicide doors front and rear) still in construction in 1942
- actual prototype damaged during the war then rebuilt in 1945 (still with suicide doors front and rear); it remains unaltered until 1947
- in 1948, the car is altered (new door handles, regular rear door)
So, my final answer is : "BMW 332 Prototyp, 1948".