I got some Sipik SK68 clones from tomtop recently. I decided to throw an XP-G I had lying around in one for improved efficiency. In general, I wouldn't recommend it to anyone thinking about it, but since I did it already I decided to go with it. The problem is that it wasn't nearly as bright as the stock XR-E. Drawing inspiration from Firelight2 who modded his SK58, I added a reflector to my SK68.
Here was the reflector donor.
It was a freebie AAA keychain incan light I had gotten from somewhere. I ground it down to fit and glued it in with some silicone glue.
It wasn't perfect, but fit well enough. Here's how the head looks assembled.
And here are some beam patterns on weak batteries so I could take close (1m) pictures without washing out my camera. First is full flood (with new slight hotspot from reflector) and second is full zoom.
In general, I am not sure it was worth doing the emitter swap, but the addition of the reflector makes the wider light from the XP-G not be completely lost. It also gets rid of the rings in the stock configuration in flood, but adds artifacts in zoom. It is also brighter in flood mode than stock, but dimmer in throw mode.
I think I will keep it like it is since it's very nice to use in flood mode, and although it suffers in zoom, it is still largely serviceable for how I use it on eneloops. I might swap the driver one of these days too to get some more modes.