Lynce, I think I have a solution to the colors on the sidewalls (Branded) not matching up to the colors of the tires itself.
You can delete the gray part of the sidewalls, so the tyre color shows through. Or, you can erase the top part of the gray with a smooth brush, so the color would blend in with the rest of the tire.
And Scavier should also make the sidewalls be affected by shadows. That is the reason your sidewalls do not match colors with the rest of the tire.
Hope I am clear. Want me to post an example?