OK...Just to make sure I have this straight...
 

IMS failure bad. Newer Boxster good. But older Boxster (1997-2000) have double row widgets so THAT IMS incarnation is more robust and less prone to failure?

Yes, but they can and do fail as well. None of the different designs were bullet proof......

Although logically you would think double row would be more robust but I think in practice, when the bearings start to deteriorate its the same result.

The double bearing may buy you a bit more time but the end result is inevitable if you don't catch it in time if you are in the unlucky 5% that may experience an IMS failure.

The problem is detecting the beginning of the failure.

By the time you see an oil leaking it probably at the critical stage.

Checking for metal particles at an oil change is also hit and miss.

The IMS Guardian is a decent alternative that monitors for metal particlels in the oil constantly.

Good info...thanks.