I don't know about by-passing for the DVD, but since it is tied into the units antenna, I would say no. However, I have not tried playing any movies while in motion. I think some people have done the mod to stereos that contained navigation (Kenwood, Alpine, etc). I believe units those are tied to the parking brake. As for Nav and Sirius operation while in motion, I have no issue. I can make changes to my route and set up a new route while in motion. My Sirius is the same can make channel changes without any issues.