Looking for comparisons between all the dvd formats: I understand Superbit is THE BEST picture and sound? Special Editions (SE) may have DTS and 5.1 sound ... isn't this normal on all regular dvd's? Normal are obviously normal... Back-ups ... On their own they are illegal. If you have a proper back-up (for whatever reason you want to preserve your original!)... would these be inferior quality in sound and/or picture to the original dvd's ...??