i like the backdrop being black and white, but I think the Bluring has gone a little too far, the fact that the grass next to the wheels is blurred makes it stand out that its been photoshopped.
Try bluring the background but not as much and keep the foreground (grass area) in focus to match the car.
Are you a member on STOC?? I used to be there, didnt make it onto the stand last year though.