Sorry this didn't tip the 5 scale. I think conceptually this was an almost there kind of shot. I think anybody who chose not to include text in this challenge was hurting with the score. As it was an advertising challenge, a much more graphic feel was needed to score well.
From a technical point of view, I think you are hurting a bit too. The image is quite over exposed, especially in the sky area. What would have helped you a lot in this specific case would be to use a circular polariser on your lens. So not a photoshop trick this time! The polariser would have helped make the blues bluer and yet keep the clouds fluffy and white.
That said, you could have also fixed it to some extent, very very easily in photoshop. The highlights in the clouds are just a bit too blown out to do much in PS.
Perhaps think about bracketing your shots to get the optimal exposure in the future. The histogram on your camera is your friend. Check it out, if the histogram is strongly to right, you have overexposed the highlights, or if it's strongly to the left, you have underexposed the shadows. In both cases, it's nearly impossible to get any detail back in post processing. If you set the camera to bracketing mode, where it takes one at what the camera thinks is the correct exposure and then the next 2 images will be a 1/3 of a stop (if that's what you have set the bracketing to) under exposed and a 1/3 stop over exposed. That way you get a more accurately exposed shot and less work to do in PS. Doing this can help as sometimes the camera doesn't get it right!
Concerning the composition, I think the angle of view could have been improved. As several people commented, this seems to be more about the man and less about the car. Moving him to the other side, would have been a good idea. Also, you do have a bit too much sky, which again takes away from the car.
As I said, though, the concept was good and some small changes to both the composition and exposure could have brought it up at least to the mid-fives (even without the fancy graphics and texts).