Torsion bars tend to break when the cars sit long periods of time.I have never had a torsion bar break on me after owning quite a few of these. I would look into it and make sure that rust is not the problem, but maybe after the high miles this could happen.
I've had them break on two cars when they were stored over the winter. One of them was a relatively low mileage (80k mile) 15 year old Cordoba.
If this is really a 51k mile car (or even a 151k mile car), it sat a lot.