Thank you guys for your comments!
No one special, but in general I have Sherwin Williams. I just go to an automotive painting workshop, and I give them a little amount of the color that I need and they make the mix until equal my color.
I always ask glossy colors, this make my work easier, especially with decals and metalizers. Once applied the decals, I apply a flat coat.
Actually, I only use enamels as color reference, or applications in very small areas. I'm saving a lot of time and money using automotive acrylic paints... you just need to be careful with your health, using mask and air extractors.
But may be you could get automotive paints of the new generation, water solubles...