So... this has been bugging me for a while now: when you are playing a time trial and change the configuration by switching your vehicle, the game reloads the entire map too, instead of just the vehicle. Seems a bit pointless to me, and is quite annoying (especially on big maps like Italy). I wonder why this still hasn't been changed, as it has always been this way. So I'd suggest to just reload the car, and not the complete map. A second improvement could be made when switching to a different time trial (but staying on the same map). Again, the game reloads the whole map instead of just deleting/adding props and relocating the checkpoints.
The same should be done for scenarios and campaigns. The latter usually only uses one map, and it would significantly speed up load times.