There are a thousand and one ways to chav up a car and tastes vary form country to country. The Peruvian top mod seems to be a blue neon light around the back number plate. Apart from its dubious esthetic appeal, it has the advantage of making the number plate unreadable.
I got it slightly wrong above. The trick is to have a blue neon light around both number plates. But I discovered last night that blue neon is only for the ordinary chav. The top chav will have purple neon lights! And the top of the top is to have both colours around each plate. I also got it wrong in that a blue neon light doesn't make the plate unreadable, a greeen one does. Green is probably for the eco-friendly chav, who will also customise his headlamps so that they glow green rather than white or yellow making them totally useless to light up the road: not light polution, result!