Welcome to the forums Gavette. What version of Pro-E and renderer are you using? It will help to know when giving you suggestions. Nice models, I recommend in your renders to use a subtle floor to put your models on and use the room to cast reflections and shadows. That way your not puting the focal point on the floor.
A couple of those cars are real nice, I like the black and grey one the best.
For those of you that are gamers, I was contacted by a video game developer for the 360 and PC. I will be designing a Dodge Charger police cruiser for an upcoming video game in both platforms. The game will be called GangCity. I plan on puting the Belair wheels on it so you will see the C logo on the wheels. I have a year to complete the final model including full interior and exterior, working suspension and steering.