There's some rubberband AI scripting going on with some of the later challenges.
However there's really only one Mission Challenge, 8-6 @ Blue Moon Speedway, that truly felt scripted. If you draft at Fuel Map 6, the leading cars will match your pace until they pit, giving you a chance to win without pitting. If you gun it with RS tires, by lap 4 they'll match your pace then becoming rockets, draft them and they'll still pull away, and you have to race perfectly through the corners to win.
Save for 8-6, regardless of AI performance, it really boils down to knowledge of the car you're driving, knowledge of the course, and knowledge of tire wear/fuel consumption settings for that challenge.
Unfortunately, the last one can only be done through trial and error unless you watched some videos previously to save you some time. Knowing the course helps immensely, regardless of what car you're driving, but whether the current car they give you is something you're comfortable with is a different story.
I felt like B-Spec Bob for quite a few of these challenges. Rally Cars at Fishermans Ranch?
Machine skill: 0
Course skill: 0
Battle skill: Destruction Derby 100
Some of the challenges I had to take the dynamic programming approach. AI cars would be roughly in the same spots at xx:xx of the event, so as you get better at knowing the car/course and where the AI will be, you'll progressively get better, until you win. This was especially the case for me at those Tokyo highway challenges where had you pass cars at unsafe speeds until you finally found your rhythm to pass all of them (figuring out car handling, grip levels, best line through the traffic, etc).
Don't be afraid to turn on driving aids, they're there for a reason. Traction Control, Active Stability Management, Anti-lock Brake Systems, they will save tire life and reduce the chance you will spin out, and maintain line through corners. I've been stubborn at not turning on ASM on Challenge 8-7 that took me hours and hours to Gold.
I actually failed to Gold the final challenge my first try despite maxing out my car's power/weight ratio... because I didn't know where the pits were at the 24h Ring configuration as I barreled through the starting grid and had to double back. Then I thought it was a good idea to slap on RM tires. I was so angry at myself the next half hour redoing the challenge... which I thankfully Gold'ed with over a minute lead.
