goldy has messy front cos i chose the colours by eye and used a big brush and slapped on that kit with fat horisonal strokes. rallywing messy cos perspective / skew changes to match cars angle screws with quality a lot, and i wasn't getting paid so no need to fix it :P
i've got some tips for yours, the reason it looks 'cartoony' is because it looks like a layer of black was put over the whole car, which makes the whole thing darker. the thing in real life is that the reflections would still be there and still be as bright as it would on any colour car. did you just increase the darkness to make it black? my suggestion would be to greyscale the car, then decrease brightness and increase contrast at the same time :P going black realistically is harder then changing to a different colour realistically.