I have often thought I would prefer it all the same color. I remember a Silver SVT that was the same color and it looked great.
I have a small scratch or scuff in the black area and guess what color it is underneath. It is red and matches the rest of the car. It looks as if the factory origanally painted the entire rear bumper the same color as the rest of the car and then pained a portion of it black. Maybe I should just break out a can of rubbing compound.