It's not really the FFB being too heavy, it's more the 'center spring'. The steering wheel is always trying to get back in the center and stay there.
I played a bit with the FFB multiplyer numbers, but lighter or heavier, that center force seems to be dominant.
Hi Fanapryde, @Ken134 ,
Excuse me, root cause isn't FFmultiplier.
Is the Steerassist.
I've tried with a 0.600 value and didn't shakes.
Erase data.acd file of the main car folder and modify STEER_ASSIST value in the car.ini.
I hope it will solve it.