December 1, 2012: I replaced the headlamp bulbs on the Boxster today because one was burnt out.
Even though only one bulb is burnt out, I decided to replace both.
The Boxster takes H7 bulbs. Both my 2004 XJ8 and 1998 XJ8-L used H7 bulbs. I had to replace three in each of those cars. This burnt out bulb in the Boxster makes 7 burnt out H7 bulbs over the course of 4 years, which seems extremely high.
The headlamp assembly must be removed to gain access to the bulb. It may sound menacing, but is actually quite simple. The fastener that holds the assembly in place is accessed behind the trim in the front luggage compartment.
A 5 mm socket, (or the special tool in the owner's packet), is used to unlock the headlamp assembly.
Twisting the socket unlocks the headlamp assembly, which can then be pulled away from the body.
This is actually a very well designed system. The headlamp assembly slides on the tracks seen in the plastic in the photo above. The metal rod rotates to lock the assembly in place.
With the headlamp assembly out of the car, replacing the bulb is a simple matter of removing the connector and releasing the clip.