Thanks!! Yeah its a nice design, I modded my first one with a 5K tint XP-G3 and the output is insane. Goes toe to toe with the ~360L mode on my E35UE, its slightly brighter actually... pulling 3A from two eneloops. I'm looking for a second one to mod.
I have the first generation E21 with the XPE emitter... thinking about modding that one too.