I consider this car as a fail, especially the back of it, but it doesn’t mean i can’t make a nice rendering of it
i hope i’ve learned from my mistakes, i need to practice more and start with simpler cars (this is the third car i make)
The paint shader makes me think it is a Matchbox toy some reason . . . not quite sure why 
Fail? I think, the model is very detailed and looks very good. if you change the materials, the car could look very realistic.
some tuning on the carpaint and the environment, + some rendertweaking and your good.
always try, fail, learn and practice, then you will get better and better 