Shadow needs to be darker under the car. Wheels look a bit to contrasted. Color change is good, but I feel the color shouldn't be as bold. The reflections from the ground should be a bit bigger. Exhaust should merge from dark to lighter, giving the illusion of being underneath the car.
Other than those things, it was a good choice on the background and the mods are done well. Just those snags that are letting it down a little in my opinion. But great work, you will get better in time
