to make it fit you'll need to re-compress it. Get tmpeg, rempeg or preferrablly CCE. On
www.doom9net there is a java based calculator that'll give u the CCE settings required for it to fit on a dvd or cdr based on the settings (mins of film, audio rate, media u wish to use) that u provide.
And no it's not better to rip it with lower quality sound, what's the point of dvd with stereo sound?