DVD is a delivery format, end-of-the-road, by concept not meant for further processing.
the iApps just support firewire connected miniDV camcorders (and a few stills with mp4 recording)...
to edit DVD you stumble into the following hurdles:
1) as the A tech told you, non-standard-shaped disk can damage slot-ins; you need a tray drive...
2) the mp2 needs conversion... some tools on the market. apple-mp2-plug-in (20$)+ free Streamclip, from here
http://www.apple.com/downloads/macos...treamclip.html
or, more convenient, less options: DVDxDV,
http://www.dvdxdv.com/DVDxDV.overview.htm
any many others...
3) converting mp2 into editable files is a lossy process; due to the nature of DVD, the computer has to "estimate" content...
after all that said:
want simplicity & convenience of the iApps? stay within concept/limits of it, get a miniDV camcorder.. a 3ccd offers superb pic quality (way much better then any DVDcorder)