Just had my IMS bearing replaced by my long time mechanic - specializes in Porsche and BMW for both street and race/track cars. The owner is a solid engine builder. Here's the background... 2001 Boxster S with 15,000 miles. I bought the car last year from my friend with about 12,000. It was his wife's car and the dealer maintained it each year. She never really drove it much (as you can tell) as they quickly had a few kids.
I had no external leaks but once the started tearing apart the car, my mechanic said the IMS bearing was showing signs of a light leak. It was a single row bearing.
I used the L&N kit, also did RSM and AO separator.
Glad I replaced it if for nothing else than my own peace of mind. Especially as the car wasn't used much over the past 10 years and wasn't driven hard... before me
Vince