So, here are my first attempts at rendering.
Number 1:
sun-ish lamp, maybe I should use a plane over the car as light emitter, see that shadow in the hood, it's from the left side mirror.
http://666kb.com/i/ap8cihwc0fyom1x5t.jpg

Number 2:
UF1, that weird reflections on the air intake are probably caused by the low poly models.
http://666kb.com/i/ap8ckuzzwuqp7jjfl.jpg

Number 3:
XRT, darker scene.
http://666kb.com/i/ap8clt6cjrykk1o2p.jpg

they're a nice start, but maybe you should cahge the location of the light