I would love to have a g-force output available to plug into my controller's rumble capability. When driving my daily commute I've noticed that I make many adjustments based on how my body feels as it reacts to the weight of the car's momentum. An example can be when I suddenly lose that pull in a sharp turn I know immediately when I've lost traction. Does g-force already play a part in the current FFB functionality in Beamng? As far as I could tell I only feel the grip of the wheels, and not really the weight of the car. While translating all 6 axes of g-force isn't really possible into a controller, a single adjustable ramp (linearity slider) that would represent the total g-force applied to the car would do the job just fine.
We cannot choose such things - the force feedback system simply reads the physics data at the steering rack, and this is sent to the steering wheel. It's not a set of cherry-picked factors, instead it's the natural results of the physics acting on the vehicle. If you don't feel the weight of the car, it's possible that either the vehicle steering/suspension design/setup is not very communicative itself, or that the USB device force feedback settings are not correctly tuned (more info on setting it up here). Furthermore, we don't officially support vibration devices, only force feedback devices. If you have an xbox device and you enable FFB, you'll just get more vibration the greater the forces on the steering rack are. All of that said, we have experimented with artificially adding extra torque on the steering wheel based on the lateral g-forces. This is completely disabled by default, but you can enable it in Options > Controls > Force Feedback > Edit binding > Side Accel Feedback. This may improve the feeling at times, and introduce unnatural responses in others, so enabling it is a matter of personal taste.