The tyres don't look like they are supporting any weight at all. Flatten out the bottoms of them a little a make them bulge outwards.
On the topic of lighting, I used two ring lights around this car, and it turned out quite nice:
They were basically just large hoops positioned so that the car was in the middle, at different heights.
And the angle of the camera in your render isn't particularly great, try going for more extreme anlges, and keep the car central, or so that the 'empty space' is the the front of the car, so that the back is nearer the edge of the image.