Are you sure it’s not the viscous coupling (presuming you still have the mechanical fan in place) the bearing in these goes and makes horrible noises. It failed on mine and I’ve been fully electric ever since.
I assume you’d do damage to the crank/bearings at some point. Hard to say without knowing how bad the vibration is.
How do you know the balancer has been tampered with? Did someone knock it/bend it?
Not too hard to replace if you don’t mind pulling your radiator and getting some big sockets in there.