See this 1,187 reply long thread:
For AWD owners wanting a P3D-
The answer to your question is: possibly, but not fully confirmed
The very "TL ; DR" (too long, didnt read) version of this from what I remember is:
1. Some people went to pick up early Performance models, and arrived and their cars were AWD. Tesla flashed the firmware on some of those, turning them into performance.
2. Lots of discussion about "binned" motors, since early AWD and performance cars had the same part numbers on the motors. Parts catalogs showed same replacement parts originally for the AWD and Performance motors.
3. At some point, the PN of one of the motors changed.
I stopped paying attention to it, so may have some of that wrong. I have no vested interest in the answer, as I have a model 3 performance already.
My suspicion is, (and its just a guess) that unless tesla can offer ALL purchasers of that model an upgrade, they wont offer it to any. meaning, if there are binned motors in some of them, or, alternatively, it would work on cars with the same motor PNs but not work on later AWD with a different part number, they wont offer it to any. If they offered it to SOME AWD owners but not all, that would be a Q#$Q#$ storm of EPIC proportions. Also, if they WERE able to offer it to all, and did, then you have the issue of the price point.
Tesla owners have PROVEN as a group that they can....not.... stand... anyone possibly getting something for less than they paid for it, and raise a stink any time this happens. If the price was too low (not a big enough charge), performance model owners would throw a fit saying its "not fair" that AWD owners are getting it for such a price, etc. If the price is "too high", then AWD owners would not just be happy they could buy it, but many would then complain about the price and "what is tesla smoking with that price?!?!?!"
All one has to do is see how people complain about new features in firmware that cost nothing, to see that this would happen. Not sure the uptake in money would be worth the negative press on it.