Try Dr Colorchip. Its a kit and works pretty damn good.
I used it on my Radiant silver metallic CTS..while metallics are hard to touch up with the flake orientation (nothing is perfect), it definitely hid them where no one else would really notice them.
I used it on my Radiant silver metallic CTS..while metallics are hard to touch up with the flake orientation (nothing is perfect), it definitely hid them where no one else would really notice them.