I dont know if this feature is in development, but my sugestion is to provide the user the feature to modify the exhaust system to change it’s sound.
In the game all engine in the same category sounds the same, and I would love to change the sound of my cars.
Been suggested before. Not going to happen. It is a very hard thing already to get it as it is right now.
There is a search box in the right top. Look for suggestions before asking them (if you haven’t done so already)