There was some recent debate among lighting experts on the gray cap-like. Its purpose is not fully understood by our scientists lolll other than only preventing someone to be able to look head-on to the filament. That's all it does - I'm serious. Expert on the other hand recommend against it because they have established that the energy get condensed in this area alone. Similar to what a even layer of body/finger oil does to a glass bulb. Therefore blah blah blah lighting this and that melting fire, explosion, ppl dying. You can guess the end

That's would be much interesting. Just stand in front of a wall at night and see the difference with or without inner lens.

Can anyone post a photo of a boxster with no-diffuser headlights installed? I'm intrigued...

This discussion is academic. As already mentioned, anyone going to the trouble of tking the headlight apart should install the projector retrofit.

I couldn't agree more here! We are making those projectors as I type, hopefully be able to advertise those shortly.

I personally think they look a lot better with the diffusers on. The diffusers make it look like one large unit and hark back to the look of classic 911 headlights. Without it (or the Xenon upgrades) it looks a bit cheap.

Side note, the half dozen headlights I've opened up here in Aus all have only a half diffuser, the bottom half is open and the ridged lines on the bottom of the inner bowl 'cover up' the gap visually, quite clever design. Not sure if that helps with the heat... probably not as they were mostly yellowed as well.