Especially in the case of a car, “The Almighty Product™” must look pristine. I’ve watched them shooting commercials in Death Valley, and they polish the car both at the bottom of the hill and at the top.
There are, if I may suggest, a few lighting issues that you should think about:
- In the original shot, the rear of the car in the vicinity of the spare-tire is, IMHO, too dark.
- In the shot in post #30, the right fender is blown-out white, and there is no detail in the tread of the tire. While the lighting on a car should be very, very high-key, this render in my humble is losing detail on both ends of the lighting curve.
Having said that, if you are rendering to MultiLayer or OpenEXR (as you should be), it may well be that the detail is still there in the file; that it’s simply being clipped against 0.0 and/or 1.0 in your present conversion to a picture-file. This is easily adjusted with Curves nodes in the blend-file that’s used to perform that post-render conversion, if the data is there to be had. (Such is the beauty of HDRI. Maybe.)