One or two DVDR and a Ifoedit problem

[Sphaa]

First of all an easy question
Should I use one or two DVDR when I convert this film to keep the same quality?
- 3t44m long
- Divx 5
- 4 cd`s

Second question is about Ifoedit
Sometimes when I convert an m2v file (from TMPEGEnc) to VOB/DVD whit IfoEdit, The video is ending up going at 1,5x speed .
The sound is just fine
The m2v file is fine
What am I doing wrong?

Please, please help