FREE Solution! No DLC Cars needed!
My weapon of choice is the Ford F-100. I tried the Holden Torana A9X at first but the Ford worked better. I only chose it because it was very high on the rankings on a Zone that I couldn't 3 star with the Holden.
Car: Ford F-100
Tune: Drift by TYGAxxxx (A 729, 5 star rating)
Cost: 36.500 Credits for the car (iirc) and around 103k for the tuning.
The Torona-tune is from the same guy.
Makes it easier to 3 star the Drift zones. I still have trouble with some (maybe because of winter) and will update this solution once I 3 star everything. So far it's just enough to reach level 10 and get the achievement.