[Perfectlap]

I'm surprised that your indy recommended against changing the bearing. First of all having a sealed bearing inside of the engine is a flawed idea from the start. With this approach, the bearing becomes dependent on proper maintenance and driving habits.

If the previous owner was not good about getting the oil changed regularly (at least twice a year imho, or every 4K miles) and did not use a quality oil if these intervals were exceeded (some Porsche experts disagree that Mobil 1 was suitable for long intevals), and the driver did not keep the revs up regularly during drives (at least 3K RPM once the oil is up to temp after about 7-10 mins driving, or twice the coolant time) and did a lot of short shifting at low revs to save gas or to "go easy" on the engine, then the bearing was not operating under optimal coniditions. If that situation goes on for a long time the bearing will need to be changed sooner than later.

And simple logic will tell you that a sealed bearing will not last indefinitely, even if properly maintained. If your taking down the transmission, something you may only do once or twice during the the life of the engine, you should replace the IMS even if you don't opt to replace with upgraded ceramic bearings. Keeping the OEM metallic bearings in for too long opens up the possibility of contamination from bearing degradation. If the maintenance practices of the previous owner were at all a question mark to you as the new owner then there's no logical reason to keep the original bearing in place. Looking back now many believe that the factory/service depts were recommending intervals that were far too long and oils that did not offer enough protection for these intervals, neither did they advise their customers to keep the car from sitting for too long, refrain from using the car only on short trips or driving the car too gingerly as far the rev counter is concerned.