Question on S6 availablility

[VFChris@aol.com]

Does anyone know if the North American version S4 (called S6 in its final
version, which I think was about 1996) was available with the four wheel
traction control system (I believe called Automatic Differential Lock (ADL))?
If so, in what model years could I find this feature?  Is this only in the
"very rare" 1995.5 S6?  Is it available later in a Canadian specification car?

Please respond to me personally, in addition to the list, since I am not a
list subscriber.  Thanks in advance for any help.