relatively few people know how to view the bitrate of a dvd. i really only know of one program myself, which is Bitrate Viewer. if anyone has other programs that they use to view dvd bitrates (i know of plenty for avi), feel free to reply.

as for the lower limit, i'd say to try to stay above 2500kbps, and this is assuming you're using a quality encoder like CCE. this is also dependent on the source (not talking about bitrate this time, but the actual onscreen action, etc), as there are movies that are inherently harder to encode than others as a result of motion, images, etc.