NA version of a modern diesel engine doesn't make much sense honestly so in this case no and yes, intake and engine covers are detachable
I have found this thread, if anybody finds it useful https://www.beamng.com/threads/scratch-decals.34252/
I agree quite alot, but seems to be a dead end until either devs or some really talented individual realizes how to do it realistically.
I made something... Might add a separate controller to make it easier to select the modes because there are so many of them
I had to do some digging in the game files I didn't know existed and use LUA functions to call other LUA functions, but I did it! Should make the mode selection a lot easier! No console errors either, everything works properly. EDIT: added independent mode selection Not all modes can be selected because there are simply too many of them for the keyboard lol