Any sources for the "bad batch" idea ?
The usual explanation for failure at low mileage is lack of use/infrequent(time) oil changes/ the misalignment issue and the load rating of the single row bearing vs double row .

I was thinking about this "check oil filter for metal " etc.. But wondering if it's a Sealed bearing from factory wouldn't the metal "flakes remain in the contained bearing ??

Metal from other areas in engine would show up , not so sure about the IMS bearing

Having personally removed my share of factory bearings, I can tell you that I am yet to see one of these "sealed" bearings that didn't have the shaft behind the bearing full of oil; so if the oil can get to the shaft, the debris can get everywhere.

I would still worry. Of the bearings that we have seen fail, many were between 50-100K miles, and a couple over 100K. There is no "safe" mileage zone.

Oem IMS bearings are very close in design to wheel bearings, they are permanently greased and have seals to prevent grease from going out, dirt from going in and oil from washing the grease out, when seals fail bearing will fail, think of a wheel bearing without the seals, it will fail quickly, It has been discussed a lot if the ones that actually failed it was due to bad oil that affects the seals or extreme pressure/ vaccum in cranckcase or just a bad batch, I would say if you are not replacing it do frequent oil changes, make sure you have a working AOS and drive it often.

My experience. Purchased a 2004 Anniversary Edition with 31K July, 2015. I did my own PPI as I had researched for a year prior to purchase and have the mechanical ability. I knew the risk of a garage queen with partial records. Drove the car home (from Buffalo 5 hours) and parked it. Called a Porsche Indy and made my appointment. 6 week later I had a new LN Pro IMSB, AOS, Clutch, chain tensioners, serpentine belt, spin on filter, filter magnets and magnetic plug. The hardest thing to do was to look at the car for that 6 weeks while I waited for my appointment. However. it gave me time to explore the car and detail it to nearly Concurs condition. Sorry back to the topic.

What you choose to do is your decision. I, much like 10/10ths, wanted to preserve the car and drive it worry free. The car remains a garage queen (now 36500 miles) and is an excellent example of the best of the 986's. Hell, 20 years from now it may even be a classic, but who cares.

From experience, I really do not think that the AOS condition has much to do with oil intrusion of the OEM IMS bearing. For the most part, the seals just harden over time, and with the bearing partially submerged in oil, and the shaft itself cooling and pulling a very slight vacuum on the IMS bearing as the engine cools after shut off, slowly washing the grease into the shaft and out of the bearings. This is the reason that the every shaft we have ever seen during a retrofit is at least partially flooded with oil.

My 2003 986S failed two months ago with 105k miles. Don't buy into the "good at 30k good for 230k" fallacy

IMS Issue
 

Mfm22 has a great deal of input from the forum - so please tell us what you've decided to do!! Thanks.

+1. The real design flaw.

So, again....
 

....just change the damn thing.

If you want a 986, just know that you will replace the IMS. Period. Just add $2,000 to the sticker price. Done.

Easy.

Change.

The.

IMS.

Just do it and start enjoying life.

Now I'm done. Gotta drive.

I used to worry about the IMSB failing. Replaced the IMSB, clutch and RMS in my '03 at 25k miles for $2100, and now I don't ever think about it. The ceramic bearing is good for 50k miles and the clutch should easily last that long so it will have to be done again at 75k miles.

I found a local independent shop that had done a bunch of them. They showed me boxes of failed parts from ones that didn't get it done and few near failures that they replaced just in time.

It's a real issue and if it bothers you, get it done and never worry about it again. I'm glad I did.

What pray tell did the "near failures" look like. I've always heard that once the metal starts falking, it goes everywhere including very narrow oil passages and some inventors of these things won't install any IMS in such an engine. So I'm interested in how they determined it was "near failure" but OK to install a new bearing.

Mostly rubber seals on the bearing failing. Oil intrusion, no grease left in them.

Dave is correct.
If Porsche had specified a Viton seal, perhaps they would have lasted longer? But the vacuum issue would probably have defeated even the Viton seals.
Ironically ,specifying 1RS instead of 2RS -only one standard Buna seal on the inside of the bearing would have been the best solution? That is what many aftermarket replacements do. And the bean counters would have celebrated the saving of the cost of 1 seal and the Porsche owners would have enjoyed longer IMSB life?

Really what porsche should have done was to have a regular oil lubricated bearing as in a camshaft or main. But too late for that

It already exists in the turbo engine used in the 993, and would have been way too expensive to add to the M96/97, plus Jake has already patented the design for the LN IMS Solution.

Just do it if you want, dont' if you don't want to. Its a very low failure rate.