Wow. I can throw away what I thought I understood and start fresh.

That's insane!

This issue happens to me when the steering angle calibration inside of the VSA module is way off. I get the four wheel speed sensor codes, as well as a yaw sensor internal fault. The VSA module will see the steering angle come in over CAN from the EPS module and then apply it's own internal offset, so if you drastically change the front end alignment or take your steering column off and put it back on a few teeth off, it's probably seeing that the amount of G-force in relation to the steering angle doesn't make sense then faults out.

In my case, after I messed with the steering column during my engine swap, it *always* faulted out in rainey curve at Laguna Seca (super long left) because I think it was meeting some conditional time that g-force/steering angle dont correlate. When I opened up the live values in techstream, the VSA steering angle was 10-15deg off of the actual EPS steering angle. So I just drove the car in a straight line in the paddock, came to a stop, and then zeroed the VSA eps calibration.
No problems after that in rainey curve.