The key on syncing is getting both audio tracks (really probably 4 tracks, 2 stereo pairs) into the same format. The audio on the MiniDV is going to be 16/48. So, you might want to take the DAT source and get it into 16/48 first. Then bring in the DAT 16/48 into your video editor with the MiniDV footage. Having both sources be 16/48 with help tons in keeping sync over long periods of time. Also, you can usually blow-up/zoom-in the sound waves in the tracks really big, which can help visually sync the sound as well. Finally, you can employ some phase cancelation on purpose to help with the syncing. Reverse one track, so it tends to cancel the other track. If you're getting bigtime cancelling, you know your sync is good (then flip it back of course). Since, I think, you are just ditching the other audio altogether, I'd just make sure to get the DAT source to 16/48, then try to sync it to the video. Finally, on the AC3 front, I guess that's just a habit of mine. When I author DVD's with video, I pretty much always render out to Dolby Digital (AC3), which is pretty much how every commercial movie DVD you'll ever buy does it. However, you can use straight PCM if you want, but if you're video is long, you might have space problems. Anyway, PCM and AC3 will pretty much play on any DVD player with video, SACD and DVDA maybe not. At least that's my understanding.