You’ll unlock the second and third car mini games after completing Chapter 13. This does not need to be done in a single game, since you can only get 5000 points per level if you somehow finish instantly. You have 3 courses to get a cumulative score of 10,000, but if you have completed the driving course in Chapter 13, you shouldn’t have too much trouble on the first 2 courses and should be able to get at least 3500 points on each. Course 1 is the one in the story, so it should hold no surprises. I never took my thumb off and managed almost 3900 points on the second course first try, to give you a sense of relative difficulty. Course 3 is comparatively difficult and may take a few tries, but if you did well on the first 2, it should just be a matter of getting through it for 2500-3000 points. Use the to lean and keep both wheels on the ground and you should be fine.