Nope, still not working. Reflections are weirdly distorted, so the model itself could be the problem. Start with some simple integration, into static backplate, no motion blur. First try to master that before jumping into more complex scenarios. Also make sure your model is good. If there is some funky topology, no matter how hard you try, it will always look weird, because car paints mostly reflect sharply, and reveal crumpled surfaces ;)