This has been discussed several times and it looks like there is still a lot of confusion about the caster angle of the kit c hubs.....
Stock is 6 degrees.
You can look at all the baseline starting setups on petit rc and you will see that all indicate 6 deg c hubs because that's what comes with the car.
Stock is 6 degrees.
Stock is 6 degrees.
Stock is 6 degrees.