There is no way to know if any particular car will suffer a failure. The statistics apply to the group of cars as a whole.
It really comes down to how you feel. There is no way to calculate the cost/benefit, any course of action can be rationalized if you think about it enough. Relying on what others say isn't particularly valuable either since each person has a only a single data point (or a couple of data points if they've owned more than one car with an M96) to share; but a single failure or success can't predict what will happen to any other specific engine.
The best course of action that I can suggest is to do the maths for yourself. What would it mean to you if the engine blew up? What would it cost to repair? Would the expense of a bearing replacement be good insurance compared to the aforementioned costs?
Everyone is in a different financial situation and everyone has a different profile for taking on risk (or avoiding them). Only you can make your decision.
For me, racing puts a big strain on the engine so its no surprise that I have and expect engine failures (officially, I am on my 4th engine but who's counting?
). With that being said, I
plan for an engine failure every two years. Thus, the expense is built into the racing budget and engines are considered wear items just like brakes and tires. As such, there is no financial benefit in replacing the IMS bearing and I am willing to take the risk under the assumption that something else will wear out first and cause the engine to fail.
With this plan, I get ahead of the problem by buying used engines for $2600-$2750 well ahead of when I'll need them (a desperate buyer rarely gets a good deal), so I always have a spare engine on-hand. Also, I have the skills and tools to swap the replacement engine in myself so I can be back up and running for about $3K total. I realize that not everyone is in my situation, so spend some time and figure out what path would work best for you.