I would absolutely 100% advise using the actual PCM soundtrack from the Criterion Laserdiscs and not the 2.0 DD version of that soundtrack that is on DVD. The PCM is vastly superior. This goes for THE KILLER and HARD BOILED.

Should you be willing to wait, I can provide them. I have to get the discs from storage and then hand them over to my movie fan partner for recording (he has a great LD player, whereas mine is now barely functional). He will then get the tracks to me and I will clean them up of pops, clicks and crackle. They will not be de-hissed as that removes clarity.

You would need to keep the sound PCM. That would require dropping all other soundtracks, but it's preferable to 192kbps DD.

Another alternative is an upscaled version for Blu-Ray. You can upscale to 720p and do a Blu-Ray version with multiple soundtracks. That gives you much more breathing room in ensuring there are no additional artifacts added when encoding the final output.

I had the pleasure of seeing both films in theaters and I can tell you that the DD and DTS remixes are nowhere near as robust as how the mono sounded in theaters. The Mei Ah DVD release's 5.1 mix is pretty good at times. In fact, here and there it's better than the mono. But for the most part the mono has far more clarity and less of a shrill feel.

When compressed down to DD2.0 at 192kbps I actually think they are only slightly improved over the remixes. PCM rules.