This is a tough question becuase for real life cars like the VWS, BF1, RAC, and the FBM, I think there should be locked setups but don't lock them to much. I think just make the LFS User, like me and you able to edit the cars as much as the average Joe can on the street for the road cars. For the Race cars on the other hand like the BF1, and the FBM since there not a road car i think lock everything BMW can't change on the car that we can change. Also I think make it so major changes like switching the side the driver is on only able to be done in singleplayer or when the racer disconects from the server becuase you can't do that at a race track. So if the LFS Devs are still in contact with BMW i think they should find out what BMW can change when they are at race and if there are certain things BMW can't change that we can change i think they need to be locked. Know to the road cars, for the RAC i think they should lock the settings but only have the ones open that can be changed in the real car. And the same thing as the RAC with the VWS, Lock all the settings that we can do but in real life you can't really do.
A little Off Topic but i think certain major setting changes should only be able to be changed when the person is on singleplayer or something because I don't think you can change the ride height of a car in less than 1 minute becuase you got to release pressure from the springs and you may have to install a whole new set of springs which does not take 0-5 seconds. So major setting changes should be only able to be done on singleplayer but minor setting changes like tire pressure and small things can be done while still connected and on the track, but in the pits.
And I do know that BMW may not say what they can change because its a secret or something.
But for the Fake made up cars I think the same thing should be done thats happening to the VWS which is locked setups but just lock the setups acording to the cars the the fake cars are based of.
Sorry for long post and sorry as it may be hard to understand becuase when I get an idea or somthing in my head I can't stop typing.