No audio related changes, only to preloads of starfield bitmaps. Previously it was loading all starfield bitmaps (bg nebula, suns, planets) and now those preloads are restricted to what the mission is actually going to use. Also the briefing bitmaps weren't closed out while in a mission so that was just wasting memory that could be better used by something else. If you keep getting sound problems please let me know and I'll look in to it.
Are the stutters worse though? They will hopefully be reduced but definitely not gone. Much more work still needs to be done to get better stutter reduction. I have more ideas that should give a massive reduction in load times and probably reductions to stutter but there is no way they'll get into 3.6.
Movies should go in /data/movies but can be anywhere in /data or even on a CD/DVD.