There used to be many Q3 mod threads before the software was updated, now I can't find any of them unless I look for the authors. I seem to recall Goldserve and a couple others, maybe Warren (formerly Etendue, now Litemania ?) had threads so look for those in the search...
As for the reflector the old way worked this way (worked fine for me and I have five in various modded states): take off tailcap, remove battery, place body and head in a plastic ziplock or vacuum sealed bag, then place in boiling water for a few minutes. Remove, and unscrew the head. If you're lucky and have your needle nose pliers or have your slip ring pliers, you can still unscrew the reflector. If not, put the head w/reflector in another bag and boil it again for a few minutes. Remove from water/bag and unscrew it. Now tilt out the lens.
For modding, you'll want a new series of O rings. I think, you'll want a #28 and a #32 (check my posts on "trying to quantify mods to a Q3" back in April?) from your hardware store. You can get a nice UCL from Flashlightlens when he has things in stock, but you'll have to measure/mic the inside diameter of your head. I think the later versions were about 22.3mm, vs the earlier ones that were 22.67ish mm. Otherwise you can get a mineral glass lens. The lenses are thinner than the plastic factory, that's why you'll need the #32 ring. The #28 is for the tailcap switch to recess the button so you can stand it on end.
Looking at the body, you'll find a retaining ring (usually) holding down the lux. Remove that, and the lux and a metal ring and a board and a small circular spring will fall out. Don't lose the spring, and if you drop the Q3 later and it goes squirrely, it's that spring, it got squished and is not connecting properly so you'll have to rebend it. For the Zetex board, I think they come in three flavors. The old one was a Zetex 300 chip, that could be modded a bit with a Schottkey diode and a Tantalum cap, but the inductor was problematic once you messed with the sense diodes. The second one was a Zetex 310 board that had an input and output cap but no diode. I found that removing the output cap (IIRC) made it a lot brighter without modding the sense resistor. Throw in a BatteryStation R123 at 4.2V to your TWO? with an IMS20 and you'll probably be getting about 1700-1900 lux/1m (or so my wife's one does). Mine I went and threw in a TWOH, UCL, IMS, and a Nexgen Board at 833mA and it gives about 1800-1900lux/1m with a R123.
You won't need that retaining ring if you use the IMS reflector, but the larger O-ring replacing that thin POS ring that was stock is needed to help the reflector press the lux/ring/board assembly onto that thin copper spring.
The other (usual) mod you can do is grabbing a 10ohm (or 15, or 20) and rewiring the tail cap so that if you unscrew it it gives you a low mode. I used a spring from the hardware store and a 10 ohm resistor. My wife's gives about 50-60 lux/1m on low (about like her MiniM@g) and mine gives about 400 lux/1m (something about the combo of TWOH and more efficient convertor board). Trial and error in cutting the spring took a bit so that it was about 1 turn out to get a "low" light vs. all the way down for a "high." I think Goldserve has/had a 2 stage switch mod for high/low.
For one of mine, I ended up finding a battery extender on ebay (haven't seen one since) and I can use two AA's in it instead of one CR123 for extra long life and convenience... Warren had an extender to use 2xCR123s as well.
