There is a "ferry" between Antwerp and Rio. This implies that it is okay to drive in Brazil with a EU registered car. Does this also apply if I am working for 6 months in Brazil? Can I simply bring my own car and drive around?
If you are a foreign national who does not live in the Mercosul area (which is your case) and you are going to stay temporarily in Brazil, you can bring your car. But you will have to declare it to the Brazilian Revenue Service under the "special regime for temporary admission".
This means that you are declaring to the Brazilian government that your car is only for personal use, so you will not be charged any importation taxes. When you declare the vehicle you will also have to say how much time you plan on staying. Note that immigrants are not allowed to bring vehicles as baggage items.
Basically you will have to fill out a form called "Declaração Simplificada de Importação" (Simplified Importation Declaration). I don't know where you can find such form, if there is an online version or if you have to fill it out when you arrive. I suggest you get in touch with them or hire someone in your country who can sort these things out for you.