some cars are easier to do than others... the color in the picture has a lot to do with it. the less reflections in the paint, the better it will look.
my best:
http://img56.imageshack.us/img56/2222/typercars1zv1.jpg
my worst:
http://img243.imageshack.us/img243/671/pastecw3.jpg
it all depends on the original picture you go off of.
soontobe- i think this thread would be better if there are no requests. please make requests in the request Cars thread, leave this thread for finished products, tutorials, and tips.