The big problem is that there are no shadows under the car.
Cut our car, make new layer with car, make one more layer with car, but in black.
Black car put inbetween original and car duplicate.
Then change black layers opacity to like 35-50%
why the heck did you use crappy CSS car model when you can choose hundreds of nicely detailed cars made by the community?
The lens flare in the bottom left is very distracting.
Its a L4D driveable vehicle, and i used it because most community cars are a bit TOO detailed.
and TOO shiny.
I wanted it to kinda match up.