I remember that the theatrical release of Pasolini's SALO was quite a test for our European democracies. For example, here in Switzerland, we had to go to France if we wanted to see it. Nearly 30 years later, SALO is available at your local drugstore. Times change.
There aren't any extras on the Criterion DVD in my possession, apart of a written essay delivered in the case. The colours are sad and, unfortunately, SALO being extremely verbose, the subtitles most of the time hide a great part of the action on the screen.
Now for the movie itself. Everybody has understood that SALO is an allegory about fascism using the disguise of an illustration of the Marquis de Sade novel. That's all. So why all the fuss about this movie ? Simply because it was the first time that a reknown director explicitly showed on screen sexual perversions implying scatology and torture. Now if this film has stopped in any way the rise of the fascism in the world, I let you find the answer by yourselves.