This mod is basically turning the KX1/KX2 heads into more potent, more modern and "reflectorized" setups... usual LEDs and drivers are possible to be chosen from the bunch for each individual mod... The gain is flawless beam profile, greatly centered hotspot with great throw (varies between LED choice and amperage driven them) - allows more throw compared to stock TIR with better spill for side-vision... Think of it as P60 module in e-series package...
Price for modding KX1/KX2 heads is:
Nichia 219B or XPG2 or XPE2 driven at 1.4 Amps (Reflector) is $80 and include all premium materials (custom aluminum reflector, copper PCB board, latest LEDs, arctic alumina silver epoxy, customized drivers or keeping stock drivers in place) and return shipping with registered priority airmail... Price includes fixed modes per wish (example: Low/High-NoMemory or High/Med/Low-WithMemory)...
CREE XPG2 driven at 2.6 Amps (Extreme) is $85 and has same premium components like Reflector above with additional components on driver to allow more amperage to the LED for greater output... Although I've seen XPE2 being pushed at this amperage (meaning it's possible to go with XPE2 for max possible throw) I don't recommend overdriving Nichia 219B as not much is gained except heat - beast to stay within factory specs... Price includes fixed modes per wish (example: Low/High-NoMemory or High/Med/Low-WithMemory)...
Upgrade driver to fully custom and programmable H17F (by Dr.Jones) is extra $22...
Upgrade LED to XPL HD or XPL HI is extra $7...
Upgrade driver firmware to LuciDrvFT (fully user programmable driver) is extra $12...
Upgrade tailcap to McClicky (recommended for 1.5Amp, definitely needed for 3+ Amps is extra $16...
http://drjones.nerdcamp.net/h17f.html
http://drjones.nerdcamp.net/index.html#lucid
Reflector as I mark on label on heads is either XPE2 or XPG2 or Nichia219 driven at either 1 Amp or 1.4 Amps on high, usually with custom driver set to 2-mode and no memory (but can be setup any other way)... this setup can be left on high until battery is depleted... EDIT: Add $12 extra if LuciDrv (MumboJumbo) fully programmable driver with extra stuff is wanted to be used for the mod...
Mods with customized driver are optimized for single Li-Ion cell use but Reflector (XPG2 or XPE2 or 219B at 1.4Amps) is well within safe voltage for driver and safe current for primary cells - so in case of need 2xCR123 cells can be used to power Reflector mod (not with Extreme)...
Oh... the MAIN upgrade in these heads is - REFLECTOR... I try to not mess with stock TIR... reflector provide very close lux measurements and outstanding beam quality with tight hotspot so I will not play with TIR at this time... reflectorized KX1/KX2 is the way to go...