Add keybind to specific values

Hey,
I want to create a new keybinding to a specific values, for example change the "mainGain" of exhaust sound
or change "inertia" or "engineBrakeTorque" by hit the B key or K ...
like, if I hit the B key the "mainGain" will change from -0.2 to +0.2
it can be for a specific vehicle
is it possible?

Thanks