Balance shaft belt snapped and wiped out the crank sensor could it have caused any more damage to the rest of the engine? ?
It doesn't make it smoother, the balance belt is there to atop the vibration ect. Some love it and some don't, I hear it makes it more lively and rev easier. It's a bit job to replace with delete kit ie engine out, if the belt hasn't taken out the cambelt I would say have all new belts fitted
If the engine has stock internal refit all belts