That's the chain tensioner. You really need to read my article *very carefully* before you attempt this repair. I don't intend to sound mean, but if you can't identify the cam plugs, then you are probably not prepared to do this quite yet. Here is the link to the article, read it carefully, then read through it again, and post back here if you have any additional questions. Here's the link:
Pelican Technical Article: Boxster Intermediate Shaft Bearing Replacement and Upgrade (IMS) - 986 Boxster (1997-04) - 987 Boxster (2005-06)
-Wayne