I wouldn't call that stupid experiments, I'd call that try to figure something out
I don't know about the flipped interior, the sounds are backwards as well aren't they? I remember privateer saying something about the direction of animations were related to the offset of an object vs the local axis (this was also why the props rotated in wrong direction). Possibly, the interiors must be moved for the game to inverse the animations like tilting... Don't know if the interior model(s) must be moved in 3D editor or just the offset value of the root node. It will probably also affect all the camera's start positions though...