I have a feeling that its the envmap for the glass that gives the impression of bumpiness.
Otherwise it is a fine car. What modeling you’ve done for the wheel is fine and well : I am looking for some reason for that wheel not to quit the car though, as I can’t see any axel or at least the end of one, neither any bolts or nut.
Tire texture seems quite hard to grasp : always too shiny and hard, but yours is as good as they come. I like the sculpture you did on them and if you invented it then good for you.
I uploaded an untextured model of the car. There you can see that the head light are just some holes. I gave them an enviroment map then, and played a little with the emission. I think that way it gives quite satisfying results, and It doesn’t look to flat.
The other lights are just an UV map, with an enviroment map on it. Because headlights aren’t very transparent, I didn’t model them, but just applied a texture.