Looks good!
I advanced the brushes on my motor a while back - I first started at ten degrees but found that for my particular application ten was too much. Power and acceleration were a bit off, and the motor was much less efficient. I drilled and tapped a set of holes between the zero and ten degree holes for five degrees advance. It now is a bit more efficient (240 vs 250 wh/mile), the top speed is two MPH faster, and acceleration is a bit better. FYI I have a 36v rated motor that is operated with a 48v pack.
While my setup is probably running at a much lower voltage than your car, the same principals apply.
From the diameter of your brush ring, I'd guess that you moved the brushes about 5 degrees. If you notice an improvement, you may want to see if an additional bit of advance works for your setup. If your pack voltage is significantly higher than the motor nameplate rating, more advance than five degrees may work out. If you find that the vehicle doesn't respond as well as it used to you can always move it back to five or zero.
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