Don't buy Gran turismo 4!!! it's hpoeless
It's ok for a perfect racing line but when you want to be the king of powerslides
that's when the game goes wrong:
it's hard to keep the car sliding
and If you take a muscle car such as a mustang it won't behave like in real life,
In real life if you take such a car and floor it You'll be in a cloud of smoke, and the wheels would just spin until they burst , that's not the case in GT4.
And the RS4 there is an old estate version and the RS6 is old as well
You can try TDU and I don't know about an "R8"
pc (lol) but there is a lamborghini lap top
Or you could take a real RS4 or RS6 and take it out on the nurenburgring or silverstone ETC...