If you are ripping the entire contents then normally you don't need to use IFOedit to modify the IFO files unless you have RCE region code issues. Although with some discs I have had to load the IFOs and use "Get VTS Sectors" to correct the IFO files.
Here is a good place to start
http://mpucoder.kewlhair.com/Derrow/index.html