thats quite an unusual style, but I like !
If you want to go for realism you should add some more different colors to it.
What I mean: the color you used is red, in different tints and shades. A real car has also some colored reflections in the paint. The sky is blue and the ground is (mostly) a dark color.
Like this for example:
If you want to keep it in hte cartoonstyle, it looks pretty good. You only have to change the rims cause there low quality and there's no room for tires anymore.
Greetz Kevin