I've had surefire g2's for a while now and use them a LOT, one I use 30x a day at work and it's the best light on the market imo. I have four of em, and a couple other low/mid end surefires for various reasons. I like the +1 upgrade bulbs, but they kill the battery useage and aren't that much brighter. Also I've had terrible luck making them last. Only thing worse than a dim flashlight is a no-light one. I stick with the p60 and p90 bulbs and have yet to burn one out. Anyways, as most flashlight freaks I am always on the lookout for new brighter affordable solutions. I read on one of my AR boards about candle power forums and spent a few days reading over there. Apparently there are new technologies around that blow the surefire's out of the water, and cost far less to produce. Runtimes and lumens are both increased. I figured the modifications would be expensive until I started shopping around.
I found a "dropin" bulb at dealextreme for $12.50 that claims to put out 200 lumens AND increases battery life. My upgraded p61 bulb doesnt go that bright and kills batteries fast. My p91 bulb doesnt even go that bright. So I figured for that much money it was worth a try. On the forums people have said they fit a lot of surefires (they work anywhere from 3-9v so they cover more lights too), but in the g2 they don't seem to work without modification. I'd be willing to modify it if it was THAT much better, ya know? So I ordered four of em. Find out afterwards that they would be shipped out of HongKong, but it really only took about a week for them to arrive. They came in this morning.
Packaged in a bubble wrap envelope I hoped they survived, luckily they did. Pulled one out, dropped it in the g2, nothing. hrmm. I was kinda expecting this, and to have to search again for modification tips. Put it in the 9p and voila! omg this thing is bright, like super white light too. Its broad daylight right now, I doubt I can tell exactly how bright until later. I thought surefires were white light until I saw this, it compares to the HID lighting that comes out of my car headlights. Super white, almost blue tinted. Anyways, I started to search for the g2 solution and came across a lot of peoples who could not figure it out. One guy said he had to grind it down and take off the outer spring all together. Hmm, so I took off the outer spring, still nothing. Went to put it back on and noticed one end is smaller diameter than the other. Flipped it 180 from original and bingo it works like a charm.
I left out the part where I flashed myself with the 9p to see how bright it actually is. Broad daylight, well over an hour later, I'm still seeing circles/dots in my vision. haha... *******.
So I flipped the spring in the rest to test em out, and they all work great. There is a gap between the head and the housing, which everyone said there would be, but I can fill that with an o-ring and be happy. The new lens assembly is that much longer than the p60. The end of the reflector is straight out so you could take 1/8" off and move the whole thing up to close the gap without losing any light output, I'm sure thats the main modification people were talking about. The gap isn't enough to make the inner waterproofing o-ring lose seal, just lets in a space for dirt etc to get inside. I'll probably just grind down the tabs a bit and put in a fat o-ring and call it good.
These things are seriously bright. If you've never had a g2 before, it's about 3x brighter than any other light we have in our shop (mechanic) with the stock bulb. At night, in the darkness a p60 at 60 lumens is enough to be considered a weapon in my opinion. It can completely blind somebody for long enough to give you the upper hand. The upgrade p61 bulb is twice as bright, but lessens your battery life by about 1/3, and the bulbs seem to burn out quite frequently. I had one p91 ($25) burn out the first day I had it. This new $12.50 bulb puts them all to shame. I think I'd be afraid to shine it at somebody in the dark, for fear it may cause some permanent damage. I'll keep it in my nightstand lite for defensive purposes for sure, and my 9p which rides in the car with me.
Read up on cree technology, its some pretty amazing stuff. If surefire doesn't get on the cree bandwagon within the next 6 months it looks like they'll be left in the dust by cheaper, brighter, longer lasting foreign jobs.
Cliffs Notes: $31 dollar surefire G2, $12.50 drop in bulb assembly = one happy flashlight junkie.