If you are looking for the bright just out the factory look then with latex it will be difficult. Some guys get some what of a bright look by adding primary colors like black to get the shade they want. There was a paint mixing thread some where where folks describe how to tweak colors. I will try to find it. But usually most of us are not looking for a factory finish, more of a battle finish. For the finish that you want auto may be the way to go.

Ps. Oh Dave Platt was the guy that know how to mix colors to get the right shades.