I do have one question though:
What do you mean by revisions? Do you mean some sort of software upgrade?
No, hardware revision. As far as I know, there were 4 revisions:
o Semi-prototype red boxes
o Original release hardware (710 Keg and some Phatboxes)
o Original release hadware w/ better quality DAC (910 Keg, VW/Audi units, BMW units, and some other ones)
o Updated hardware w/ additional control lines (Toyota units, maybe some others)
Then there's the Ford one, which is completely different.