[Jake Raby]

Based on your year and the fact that its a Boxster the chances are good that you are losing a lifter. In 2013 we have saved 8 engines with our procedures and all were suffering the same symptoms as yours. We are a lot of misdiagnosed failures with these engines and these days evenly thing ends up being an IMS failure, even of it isn't. Today we see more if the other 23 modes of failure killing the engines over IMS issues since so many cars have been protected or retrofitted.

Generally IMS death is silent or occurs so instantaneously that the noises don't have a chance to start.

It's probably not dead, at least according to my definition of the term. Failed water pumps leading to cracked heads, broken valve springs and failed cams/lifters are what have our facility populated with Porsches from 19 states at the present.

The 3.6 factory engine is the most problematic of all, it has the same issues and even more than any other M96. Carrera engines are not special, they are just a larger Boxster engine.