Seems as though the movie was recorded in stereo and, at times, the right track is lacking.

The sound quality of all three is pretty much the same and if you want to see or hear it in better quality just try Mono 1.0 or the 5.1 mixes.
Try out what sounds best for you.

Yeah, the sound quality is just god-awful, I agree. I wouldn't even watch this one. See my post where I count the ways why you should avoid this crapfest.
However, the 2nd and 3rd movies in the trilogy are well worth it, and I highly recommend that you see both of them. The sound, although still bad, is vastly improved and isn't anywhere near as distracting.
I want the doctor to take your picture so I can look at you from inside as well.

There is no original sound, all tracks (english, italian, german, french) are dubbed.

Try to watch in the original sound, with subtitles.

I don't think there is such a thing. But I agree, the sound quality has always kept me away from this movie.
I want the doctor to take your picture so I can look at you from inside as well.