The Four Horsemen remastered-
https://soundcloud.com/officialmetallica/the-four-horsemen-remasteredI'm doing a side by side comparison with the original CD, and the good news is that there's not much difference in volume. It's a little bit louder, but the original wasn't that loud, so there's still no audible clipping or compression (the kick drum sounds a little clippy, but it actually sounds the same in the original, so I think that's just the production on the original audio). It's a little bit more trebly than the original, which I think has helped the mix all around, because on comparison the original sounds a bit lacking in those mids. The guitars sound a bit thicker, the bass guitar is more prominent, and the kick has a bit more attack to it. It's overall quite subtle, so may not be worth buying if you already have it, but if you don't, this will be good. I always thought Kill 'em All was a very good sounding album for the time anyway, so I don't think it needed a lot of retooling.
So far it appears that they're doing this right. I don't know if their approach will be the same for every album, but I'm still holding out faint hope that they'll remix AJFA, even if it's a bonus disc or something.