Both Win & Mac can use wav format.
I saved a Song.SGU on Win with Song.wav and it opened on Mac, the wav is is the Audio track in the mixer it will show orange.
The Mac version can also use the Win version Audiophile wav's
Both Win & Mac UserTracks use wav format.

For anyone that wants to use the Win Audiophile drive on Mac,
To get the Holds/Shots/Pushes to work rename bb\RealTracks\Library to LibraryM
then create a symbolic link "Library" in the RealTracks folder pointing to LibraryM
also do the same with bb\RealTracks\Direct Input\Library
this will then work on Mac and Win.
To play the Style/RealTrack/Drums wma demos set the default media player as MPlayerX or VLC etc..
You can also copy the files in Soloists and Styles folders from the Audiophile drive to the same folders in the Band in a Box applications folder on Mac.