1. twonky does not actually count time you used it for testing, it just looks at the installation date and compares it to current. then it does a little magic (some math) and makes an almost permanent mark somewhere in files.
2. when demo expires, it is still possible to access/play media over web browser (tried it with ps3 and buffalo linkstation).
3. with buffalo you can reset twonky by upgrading firmware, maybe this works with dns-323 too.
4. i managed to install non-expiring twonky on my dns-323. i think i made a mistake somewhere along the procedure (being not-too-familiar with linux) and twonky writes some of it's files to locations which get erased during restart/bootup. don't ask me how i did it, it just happened.
oh, one more thing: when i use twonky for anything else but the movies (i.e. music playback or watching photos), with ps3 or wd tv live, i get those pink drive lights, rootfs gets filled up and e-mail warnings (left hard drive has failed, right hard drive has failed) start pouring in. everything still seems to work though.
i like twonky quite a lot, but i'm not buying it until the problems with ps3 can be either solved or worked around without much hassle.