It's most obvious if you look at the headlights and the front running lamps. Also, as TinCuda pointed out, it's missing the parking lamps. But when I first looked at it, I couldn't tell. I was looking for pics to use as a Challenger screen saver, found that image, and then noticed that the guy was talking about all the rendering work he did.
Loco340 - very cool. I've seen other images of the original. I agree with everyone else about the wheel choice, but otherwise it's one sharp car.