Did you watch the video I quoted? It doesn’t replace anything, just adds the March to the “gap” in the existing music.
I think I did a little while back during a previous visit to this thread, watched it again though as I couldn’t remember exactly what was changed.
While I think it works pretty well, at the same time I don’t like it as it DOES actually replace original music that is effectively announcing the arrival of Vader and setting the tone for how you should feel about him. The piece of music I refer to is in the first 8 or so seconds of the youtube link I posted above which also ties into the piece that follows it at around the 15 second mark as Vader walks off but it is cut off by the editing of the youtube video.