I don't think that should be the how it is done. I've seen a lot of the technology out there now, and a lot of things that AI is capable of ... So how about an AI that can learn and adapt? The AI start off as stupid as they are now, but as you progress through each A Spec section, the AI can see the lines you take and the overtaking you do both where you do it and how you do it. Thus meaning that when you hit extreme ... the AI is much smarter that when you started, thus giving you a more competitive race.
Then of course you can keep training the AI so to speak by redoing races. Then as the AI becomes smarter, and races are more of a challenge to win, the prize money and XP increases to match regardless of race ... Im sure this can be achieved somehow ... maybe lessen the cars down to 8 to make more processing power available.