The Australian versions of the movie (including cinema versions, made for TV and video releases) are missing several scenes that I found in the DVD release. The entire scene where Elwood quits his job is not in the original (the factory makes the spray on glue used to cause the accident that destroys the Good Ol Boys Winnebago and Elwood steals a can before quitting), neither is the scene where they park the Blues mobile next to the power transformers for the trains (incidentally John Landis explained in an interview that Dan Akroyd in used this as the reason for the cars supernatural powers) several of the music numbers including James Browns number and Cab Calloway's are longer, with extra verses. Elwood also damages more police cars by filling their tires up with explosive gas at their final gig. These explode and cause more mayhem when they start the final car chase.
There's more but that's all I remember, I've only watched the DVD once. The original script and I believe also the original movie were thought to be too long and so they were cut where it was thought would do the least harm. Purists may disagree . . . .