I also have some streetcar-skins in my skins-folder that look more "semi-professional". I like that because you can see those type of cars on real trackday events with that kind of look. So generally
.
Now for the criticism-part:
1. Has the numberplate on the left side intentionally swapped directions? If I remember correctly we write from left to right.
2. When you apply decals like the shell-logo to your skin, resize your skin to 1280x1024 before you do that. Then apply the decals and before using it resize it back to 1024x1024. That way the aspect-ratio of the decals is (nearly) correct and they don't look squashed.
3. I'm not a fan of carbon-texture-skins. So I won't comment on that.
4. It's very unusual for the muffler to be coated in paint (because the paint is not that heat resistant). You should better stick with the metal-color that was on it before.
5. Put your bloodgroup behind your name on the car. That's a added coolness-bonus.
(For the case your car burst into flames and the ambulance needs your blood-group to help you.)
Keep on editing.
Vain