none said:

I don't think it is a different take. It is noted in the 005 guide that some of the landspeeder shots the timing was changed. Best to use one of the Split versions to see the effect over time, it is generally two to three frames where the landspeeder from the original ends up +3 or -3 frames in the 1997 or 2004.

Yeah, I think you're right. It looks like they indeed used the same footage but it is so heavily manipulated that you can never get them to match up even if you went a few frames backwards and forwards to get their timing right. In the SE the speeder is at the same angle throughout the shot, R2 is in a different position and so on. It just looks like a huge copy and paste job to save time.

none said:

The backgrounds were often stretched vertically as that made the lifting of the speeder easier to recomp.

That is only if the speeder was a composite in the first place. Not only did they stretch the background but they copied the topmost part of the foreground in order to lift the speeder, you can see the clone stamp result all over the place. Something they wouldn't need to do if the foreground and speeder was composite elements.

Also, if comparing them, try to look at something else than the bonus DVD as the DVNR on it is disastrous on shots like these.

EDIT: nevermind, adywan beat me to it. ;)