About that missing snowspeeder crash: I believe the explanation for its being missing in the 1993 mix is because it is not present in the 4-track master from which it was derived. The theatrical printmasters had it, but this earlier generation copy did not, so when the '93 mix was being made for the Definitive Collection, they simply didn't notice its absence. The track feels very quiet without it, which is probably why the 35mm version has it mixed very prominently (compensating for its prior absence). Later copies, such as the 16mm mono and the SE, dialed back the level somewhat.
I shall make my tracks available for download together once I've finished them all. It would be good to have them in a torrent or something, perhaps in various formats to be easily used with different kinds of video.
The better the fidelity of your equipment, the easier it is to hear the difference between lossy and lossless. For most people, the main barrier to hearing the difference is not any deficiency in their hearing per se, but the simple fact that great quality analog gear tends to cost quite a lot more than they are willing to spend. Once you have the opportunity to do some A/B comparisons on a real hifi system, you may well surprise yourself with what you can actually perceive.
Note that these kinds of differences are easier to hear with music than with sound effects.
For a really good explanation of the effects of different audio resolutions, watch the presentation called "Lost in Translation" by mix engineer Andrew Scheps: link
I had the opportunity to meet Mr. Scheps when he gave this talk again a few weeks ago, and he's a really cool and knowledgeable guy. As part of the presentation he set up various listening comparisons between lossy and lossless formats on some ridiculously good speakers, and in every case the uncompressed versions sounded better. His theory as to why this is true is that it's not even because the lossy was 'degraded' per se, but because removing too much information makes the sound more fatiguing and less engaging. Lossy audio forces your brain to work harder to fill in the gaps, and over extended listening periods this will tire you out mentally, making the experience less enjoyable. Higher quality audio, by contrast, can be listened to for a long time without any associated unpleasantness.