The "actor" of Ronny is actually the former childhood bully of the regisseur de Jong, as he told at the premiere at the berlinale.
The purple Lamborghini has license plates that, according to the dutch licence registration RDW, is not from a Lamborghini but a gray Ford Granada 2.3 GT.
One of the characters asks about the production year of the purple Lamborghini Diablo, it appears to be a 1993 Diablo SE30, judging from the color, bumpers, headlights and air intakes.