I have managed to successfully extract the content of a data.unity3d and edit some files, however I cannot import these edited files back to the data.unity3d, I used 2 tools:
AssetStudio
Assets Bundle Extractor 2.2
The first allows me to extract the assets but not import them.
The second does allow me to import them, but since the game I'm working on has 170 levels, it is difficult to put one by one more even when testing.
Do you know of any tool that allows me to extract the levels of a data.unity3d and then compress it again?