Here is a setup I made for the Stock Car V8 at Goiania. This setup should work well on any track with long straights and few tight corners. To use this setup on tracks with shorter straights and lots of tight corners I recommend reducing the stiffnes of the front ARB and increasing the angle of the rear wing. Keep the front ARB between 50 and 100N/mm and the rear wing between 1 and 3°. Ride height is important too. You have to make sure the car doesn't bottom out in the corners. You should therefore increase the ride height on bumpy tracks. And don't forget that the fuel load affects ride height as well.