I still am not seeing this AI slowing down and let you win thing. I thought maybe it was in the lower classes but after the race I just had it sure does not seem that way. My test NB Clubman Cup Roma.
I drove the MX-5 Miata 1.8 RS, HS tires, stock no assists. Top contender in the race was the RSX
I managed to overtake the RSX in a corner on the second lap but it was faster on the straights than I was. I blocked it the first time it tried to pass but then on the final straight I did not block it to see if it would indeed let me win. It was close but he made it past me before the line and took the win. No indication that he backed off any at all and I was on the floor in the MX-5
Edit: I also had a race in the Novice section where I made contact with the leader and spun out on the second lap. They did not slow down to wait for me and I finished 3rd
They don't stop completely, so if you are far behind of corse you will lose.
But they slow down a lot if you are not close behind them after 50% of the race.
Example from last race Allstars in IB:
They start with 1:59, if you are close to the leader in 3rd lap he starts to do 1:55.
If you are still far behind because you have a slow car they will slow down to 2:10.
That is 15sec. difference between what he can do and what he does when he waits for you !
Never found it suspicious that if you make a small mistake just in front of the leader you catch him again in 3 corners ?
In reality he would be gone, you would need a few laps to come close again.
And it definitely is not better later on, in IA they still let you win.
You can win the dreamcars with a GT3 or touring car against the Group C/LMP cars.
(First 1-2 laps you loose 5sec. a lap to them but then you magically come closer although you still do the same laptimes)
You can win the GT3 championship with any GT3 easily if you not spin in every corner.
Cart race is the same, just keep driving around at whatever speed you can do without crashing/spinning, in the end they slow down and let you win.
Joke from A to Z...