Yellow looks too "ricer". Except if you're making a bumblebee statement (hi doc), in which case it fits right in.
On a red car - I'm assuming that's your car in your avatar - I like the look of the silver background on the Acura badge. It offers a bit of contrast while still providing a "classy" look. For that reason, I would go with a silver badge on a red car, and also on a black car.
I might go for the contrasting look of a red-background badge (or possibly a black-background badge) on a silver car, and maybe even on a light-colored car (white or yellow).