I read through the service manual for both the 2003 Boxster S and the 2005 Boxster S and still have the same question regarding the TTY bolt.
The service manual is vague on setting cam timing on an engine where the timing had already been set. It tells you how to set timing on a fresh rebuild, it tells you how to check if timing is out or not, but it doesn't tell you how to correct timing on an engine that was found to be out. If it is suggesting that you need to rebuild your engine, or pull the engine out to reset timing, that is absolutely absurd.