hi. there are several basic mistakes in the picture you've made. First of all, the biggest mistake is that you resize the picture wrong. the whole car has malformed. if you use PS keep pushed 'shift' to prevent this. beacuse your car is malformed, i cant decide whether the BG is okay, or not. the shadow under the car is also wrong. it's too big and its position is not okay.
i'm glad to see that you are creative, but at the moment you dont have enough knowlegde to make your ideas complete. do something easier and simpler than it is and practice the basic stuff first. keep moving and keep your creativity in the future. good luck. HR_JR
P.S: i wont vote this time, i dont want to ruin your score at your profile.