[tomc88]

...wish I could have recorded the phone conversation - I forget most of it now, but I'll give you the gist.

These guys are a specialist at fitting LN bearing upgrade.

They are seeing about 5% of these porsche engines failing, but!
there are about 5 common reasons for engine failure and IMSB is just one of then.

They have only seen one IMSB fail in the last year, yet many others with cracked cylinder heads, or broken timing belts etc.

What I got from this conversation is that, yes, the IMSB can fail, gut it's just as likely something else will fail too.

My car is worth about £5K - the upgrade will cost around £1K. So it's all a gamble of course.
My oil is clean so I'll take the risk

This of course is always a heated subject, but the phone call did open my eyes to other engine problems that seem to get forgotten.

has IMSB failures overshadowed other reasons for engine failures?