@sook: many thanks! I've got the MME 32bit setting, and so far it seems and sounds fine to me. Not sure if that is what you mean though. I'm still a bit of a n00b at all this. I do know how bad mp3s sounds compared to wav's but that's about it so far...
 
Regarding the other issue, when you say the high latency is needed to work for them, you mean that basically there is a lot of delay in recording? And stuff may get corrupted and so on, or just not time correctly? Because I have had issues like that on a different system, and I don't have them now at all - not with Sonar, nor with Audacity, nor with Reaper. Sonar though does on occasion mess up a little graphically, but fixes itself soon, and never affects the audio. Stuff I'm talking about is waveform was once missing but audio recorded fine and waveform returned once done; a row of copied clips once had a few holes in it, but played fine and the clips came back later, and dragging audio may appear in the wrong track, but if I don't fix it myself, Sonar fixes it soon. At the very least on next startup.
 
So far 64bit Sonar has only crashed once, and that was when I was adding, previewing, changing, deleting, and adding new effects while listening to a track. I think that's kinda stressful for a small DAW, but I've usually never had this issue with Sonar. Altogether it seems quite fragile and buggy, but this setup here seems to work best of all so far: 32bit installed but not used, 64bit installed and always used.
Only sucks to have fewer effects than 32bit...

By 16bit, I meant the record bit depth. I would be surprised if any MME driver operated at a 32bit record bit depth. Still it is better than nothing.

@scook: Thank you so much for clarifying. That makes a lot of sense. To me that's a "nice to have" for now, but I know from video that bad drivers can cause crashes and bad behaviour, so I was wondering.
Good audio quality is obviously very nice. But I'm taking everything babysteps at a time, so it's fine for now.
 
Thanks again!!