Hi Klaus,
1. Deleting the directory - or put everything just in another one would be sufficient. The only thing that could remain is your settings, like which Engine you used lastly. But that's completely harmless.
2. No. IMHO not. ASIO doesn't sound right, KS doesn't sound right; Both are out of my control.
The improvements are in Vista, and if all is right you can hear that, say, each other month (but in practice it goes faster
).
I don't want to be snobbish, but everyone staying with XP because reasons like "yeah, but there my soundcard is supported", does that for the wrong reason. If you're into the best SQ possible ... well, you know what it's about.
Regards,
Peter