I've heard it rips them in WMA (windows media audio) format. It's a standard windows media player format.RIFF is just an abstract format; common examples of it are WAV and AVI. If the MMCS rips CDs as WAV files then yup... it really sucks donkey balls. Seriously...
It's definitely not WAV format; that's 10x-12x the size of a standard compressed audio file. It's not likely to be AVI either, because that's a video format.
The hardest part (I think) would be to determine what it does when the CD is ripped; if it's adding entries to any kind of internal database or doing other actions besides just creating the audio file on the hard drive.
Great work on this so far!