This achievement i found easier than i first thought, i messed up on x83 Combo with a total of 70,000,000+ Drift Points, here's what i used.
-Discipline: Drift GP
-Car: Pontiac GTO
-Location: Okutama
-Route: Drift Circuit
-Laps: 10 (20 to be safe)
-Livery: (Non-specific)
The track is mostly turns and bends but there are a few short straights, the longest straight would be the starting line, all you really have to do at those straights is swing the back end of the car out side to side. This DOES take some practice though, no doubt about it, but it is doable. If you know the game well and have played for a couple days straight like myself, you shouldn't find this at all hard, just be careful.
Keep in mind that you CAN definitely use the 'Back' button to rewind time to a point where you're drifting perfectly, this didn't affect my points on my run.
If there's anything else that you may think need updated, please feel free to leave me a comment, thank you and i hope this helps you!