kwando - there's how-to's to open a Q3 if you search. I suck at searches, but you can probably find it. For a condensed version...
1. Put strap wrench around body of light (preferably under the clip to not damage it, or remove the clip first) and another strap wrench around head of light. Twist in opposite directions (remember, lefty loosie).
2. Remove head. You'll see a silver retaining ring with 2 notices. Use a snap plier or long nose or needle nose plier to remove retaining ring.
3. Pull out or drop out (if upsidedown) the whole LED + spacer ring + driver assembly. Take note there's a small gold ring underneath the driver board, don't lose it!
4. De-solder the 2 leads on the Lux Star.
5. Solder new Star (Lux or Cree, whatever you like) to the appropriate red (positive, anode) and black (negative, cathode) solder pads on the Star.
6. Re-assemble and you're done.
7. Click - damn, it's brighter!
For the 2-stage clicky, search for milkyspit and "pimped out Q3". He has a how-to with pics. I tried mine, but did a bad solder job (crappy soldering iron with super dirty crudded up tip!) and it doesn't work that great. You just need a small chip or axial resistor of the value you like (you might want to buy a few values to see what you like most) and solder on a couple of pads on the board that's in the tailcap. A bit harder job, but not too bad if you have a clean soldering iron (not like mine which is black and won't transfer heat efficiently until it melts the board).
HTH.
