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Getting the behavior down was quite a process!  As far as getting the cars around the track I set up a waypoint system with area3ds, and the cars stored the waypoint number they were on.  So when they hit a waypoint the waypoint system fed them the next position to go to.  
For navigating to the waypoint the car checks the angle to the waypoint and sets the steering angle accordingly.  The cars got stuck on walls a lot so I had to just manually make sure the waypoints were far from the walls and the line between two waypoints never crossed a wall.  
Then for overtaking I have 3 ray casts, one forward and then 45 degrees out to left and right.  The car checks its desired direction by eliminating any rays that intersect walls or cars, then averages the remaining rays together (eg right is blocked, left and forward average to slight left).  Then I averaged that direction with the direction to the waypoint to come up with where the car should steer to.
Basically a Frankenstein of every method I found online, but I was so pleased when it all came together!