I was going to suggest what you've got there.
If you're feeling feisty, you could kick the Hot Wheels trophy up a notch by adding a platform on which the actual PPD car could be displayed. Add a piece of 1x6 (or 8?) to the bottom, and then a 2x2 piece with rubber on it (like a track stop section — you could probably use drawer liner) as the perch for the PPD car.