I wouldn't suggest a painting a whole door - at that point your more drawing then photographing. Plus it can be really, really tricky to match multiple direction gradients on something like a curved surface leaning away from you
I think the HDR shots are just overdone - if you toned it down (a lot) and or combined it with a regular image masked, you could just use the HDR DR compression where you need it, not sure the car did.
Can you post the originals, or the one that has the best look for the car?