There are several things you can do to help mitigate the risk, all of which are discussed on this board. Here is another great resource for info:I'm thinking of buying another CS this time manual. See a nice 06, around at my local Porsche... Is the engine failure a really common thing? Is it something to be worried about when buying a 06' CS with 30K miles on it?
Just know that replacing the IMS bearing in a Cayman requires splitting the engine cases, which means a rebuild. If you go that route beef up other components while you're in there, like the rod bolts and head bolts to name a few.If you are thinking of tracking the car, you are tempting fate.
If not tracking, you could leave the IMS bearing as it is, since for 2006 Cayman S it's the beefier single row ball bearing. You should check by VIN/engine code to be sure. But for piece of mind, I would replace it with an upgraded IMS bearing.
The replacement motor I'm putting in will have an updated IMS bearing.