Brilliant silver rear bumper a different shade?

JGreenwood07

The reason the shades are different is that the bumpers, side skirts, etc are are plastic, while the hood, doors, etc are metal. The porousness of the plastic absorbs the base coat and primer differently than the metal. This causes the paint to settle and refract light slightly differently and gives the illusion of the colors being slightly off.

Not to mention the brilliant silver on the 370z is extremely difficult to match. I had to have my hood repainted and had to settle on having fenders blended, as matching the metallic silver was nearly impossible. Even with the blending of the paint, you can still barely see the color shift from panel to panel.

Also, as others pointed out, sometimes the plastic panels of the car are painted separately from the metal ones at the factory and can have very slight variances in paint color mixtures.