Just did Rambo's this weekend.
I used the Halfords Plastic Bumper paint in black. (They do various other colours)
Gives a nice matt finish, and you don't have to prat about with primer and rubbing down between coats either. Drys really quickly too.
Two downsides to this type of paint:-
1. You need LOTS. I did the fog surrounds and the grills, and used 5 cans of spray paint.
2. It's also pretty noxious stuff. I sprayed in a well ventilated garage and I really suffered afterwards. Should have used mask (or even better a respirator).
Results are great though. I would take a picture, but the rest of Rambo is filthy at the moment, and he made me promise I wouldn't take any photos.