VANOS Question

Hi everyone, I'm well aware that the some E46 M3s seem to suffer from VANOS failures (which then end up resulting in a catastrophic failure in many cases), and that the failure typically doesn't have any warning signs leading up to the event. My question is whether or not BMW eventually addressed these issues. Has anyone heard of Z4Ms models suffering from this issue?

The M3 I intend to buy had its VANOS replaced under CPO warranty not too long ago. If BMW made internal changes so that I no longer have to worry about the unit failing while I own the car, that will make me feel a lot more comfortable with the car.

If they never revised the unit, how frequently should I be checking for issues?