How would one go about muffling the noise of a drone or vehicle within the rules?
For example if your game is going to revolve around lakes/oceans it might be good to muffle the noise of the engine on your boat so that it would be harder for people to notice.
If the team buys a helicopter, not having it heard when it's on an approach for insertion or extraction would obviously be nice.
A Rigger's spy drones would obviously not want to be heard.
Unless I missed something there also doesn't seem to be any differences between power types, aka a car with an internal combustion engine makes the same noise as one that's using an electric motor.
There isn't anything explicit that I can find that handles sound dampening on this scale, which is surprising in a game that revolves around stealth so much. The "Signature Masking" Modification provides Thermal and Radar masking. It does not state that it also muffles sound, but if there's anything in the game that comes closest, this would be it.