When your computer thinks a 44,056Hz wav is 44,100Hz, it'll play it slightly faster speed. So when I first tried it, the sound got slightly out of sync partway through the movie. It still seemed to get out of sync when I manually set the sample rate (without re-sampling) to 44,056 in Sound Forge, so I just made a wav of the AC3 audio from the DVD and made sure it synched up at various points in the movie.
To do this, I split up the audio into two wav files, one for each side of the LD. I then made sure the start point was at the same frame as the DVD audio, then I found a point (like a loud, sharp noise) towards the end of each LD audio file and calculated how far off it was from the DVD audio. I then re-set the sampling rate (again, without re-sampling) to match the speed of the DVD audio. When everything was in sync, I finally re-sampled the audio (without using an anti-aliasing filter since I don't believe it's needed when you're going to a higher sampling rate) to 48kHz for DVD audio, and re-muxed it with the video. It still gets slightly out of sync at one point and then gets back in sync. Probably a reel change that I didn't account for. Oh well, it's not too bad.
Anyways, rather than going through all this trouble for the OUT, I just used the LPCM audio taken from the LDs that was on the fan-made OUT DVDs I got years ago from someone on this site, I think. I forget who did them, but it didn't require much work, I just had to take out the bits of silence that were at the LD side change points and make sure the audio started at the same point as the DVD audio.
Started with ESB and finished it last night, and it sounds beautiful.