OK, want the JDM look?! :P Well, I tried this the other day and it turned out alright. It's quick too. This is my 1st ever *real* tutorial. Hope you like it!
1. Use the poly lasso and make a triangle shaped like a canard dependent on the angle of your car. Like so:
2. Use the Bevel/Emboss tool and tweek with it to get the right reflection. It's up to you on this one. Like so:
3. You're done! Stick it on your car, or just make it on your car. The finished result should look like this:
Simple, yet efficient I think.