If I have previously setup opponent classes, for example GTE/GT3/GT4, and then I change cars to a Caterham I suggest it should reset the opponents list, perhaps only if you pick a car outside of the chosen classes. Otherwise, when switching around cars, you end up with very wrong opponent classes like F1s mixed with Beetles.
I don't disagree, but this also feels like a more general UI issue. Ideally, shouldn't a mistake like this be immediately obvious from the screen where you hit race and commit to loading your choices? Having the game do hidden changes is only good if you can be sure that the user knows they're happening. The old rFactor 2 UI used to be good in this sense. Most things were immediately visible as you hovered your mouse over the race button: Your car, the track, race settings, and a list of opponents. Pretty much anything you can't immediately see is easy to check in just a handful of seconds.
