Any car can experience any kind of failure, but the 986 specific ones are IMS, RMS, D-chunk, and slipped sleeve. You can catch RMS by an oil drip that often occurs before the failure, and D-Chunk and slipped sleeve are now exceedingly rare on 15+ year old cars, as most occurred early on and where replaced under warranty.
The 986 was prone to D-chunk failure, where a part of the cylinder would fail (a D shaped chunk would break off), this most commonly occurred before/around 30k miles, and almost all of these failures where replaced under warranty. It would be rare, for a 986 to experience that failure now, considering the age/milage of most 986's. The best defense against this failure is to let the car properly heat up before revving the engine over 3000rpm.
Slipped sleeve failure is not the same as d-chunk, and affected only a few months of '99 production. Due to the unexpected popularity of the 986, Porsche could not keep up with demand and ended up using cylinder sleeves on some 1999 986's. Due to a defect some of the sleeves failed, resulting in engine failure. The months affected are though to be: 10/1/1998 to 3/31/1999, you can check your manufacture date on the driver's door sticker. However, most of the 986's affected by slipped sleeve would have failed by now (again though to happen by or around 30k miles), and it would be rare to have a slipped sleeve failure these days.
My 1999 986 with 95k miles is in the date range affected, and no issues so far.
