pittrek said:

Visual changes :

Star Wars : https://picasaweb.google.com/102542760950977079734/StarWarsSpecialEditionChangesHD
Empire : https://picasaweb.google.com/102542760950977079734/EmpireSpecialEditionChangesHD
Jedi : https://picasaweb.google.com/102542760950977079734/JediSpecialEditionChangesHD

Not sure about audio though. There are so many threads about it but there’s no search functionality right now, try to google something like “audio changes site😮riginaltrilogy.com” or something similar
EDIT : The smiley face is actually " : o" without the spaces

I think none’s spreadsheet has audio changes annotated. Don’t have the link handy, though.