What is the symptom of a defective spark plug tube

[recycled sixtie]

tube. What are the implications if they are not replaced?

[Wayne 962]

I'm pretty sure all they will do is allow oil into the spark plug hole. On the BMWs this happens all the time, to the point where the whole spark plug is immersed in oil. It doesn't seem to have an affect on any of the performance on the BMW side, but it does create a mess when you change the spark plug (on the BMWs). The Boxster has a horizontally mounted boxer config, so you wouldn't have the same issues...

-Wayne