Ozgalis, if you look closely, ( unless i see a different 'crease' ) that is a reflection of the, would be horizon line in the background, upon quick inspection you'll see that it continues top and bottom of the window along the body panels of the car, as well you'll notice small inconsistencies in the line, which translate into trees and the like along the 'horizon' of the image that's used for the hdr.
also, chances are a crease like you though that might be, would be dead center of the model, where it was mirrored / duplicated across the axis, if the artist so chose to model it that way, at least, that would be the most likely place for that type of crease mentioned.
Only three crits i would have, the shadow for the bottom of the car seems to be a bit off form the apparent light source in the background image.
also, from the ambient brightness of the sky in the background image used, I'd say that the area around the car should be a bit brighter,
Third, the car its self has a plastic/game feel to it.
All in all, i like the work. Model looks very clean.