Seems that this challenge works now:
You have to reach three goals for this challenge, the ingame counter is every time one race behind (or you have to restart the game).
1. 5 Laps on Bathurst (german description is wrong - it says 8km) in a Australian car - i took a Holden Touring Car - custom races count
2. Drive faster than 290 km/h (180 mp/h) in Dubai - again Free Roam Race (if you wan't without other Cars) - i took one of the indy cars and Dubai City Circuit 1 lap - you schould easy beat the speed target in the first lap, and it seems that you have to finish the race
3. Finish a Race in Rio in top three - again free roam - track rio mini 1 lap - a car what you like and i took all drivatars
- you also can use also only three - thanks to Sean Reinhardl for this comment
- 0 drivatars also should work - thanks @koding
Now you get your Challenge Achievement and you '32 Ford Deluxe