The short version of LED options in a G3: Due to the nitrolon (plastic) bezel, heat will be a problem.
The best configuration (IMO) for the highest practical output is the Malkoff M60L in your G3, providing ~140 lumens for 6 hours or so - an excellent configuration. The SureFire P60L LED module is probably not the best solution - not the highest of outputs as well as being rather inefficient due to the thermal regulation of the module preventing it from overheating. There are other (cheaper) LED options but none of them have the excellent thermal management of the Malkoff LED drop-ins.
I have a G3, but it has the newer aluminum bezel, giving me a few more options with regard to heat issues. It is probably not cost-effective to purchase an aluminum bezel as an upgrade.
Two off-the-wall options:
- Keep your eye on CPF/Marketplace, I occasionally see near-new P90 lamp assemblies for ~$5-10. P91 lamp assemblies are much less common but cannot be used with many of the common rechargeable configurations due to the high current draw. Needless to say, a P91 will run you through a lot of CR123 lithium primaries.
- You could try a Malkoff M30 LED and two commonly-available (and inexpensive) AA's in your G3 for ~120 lumens for 1-2 hours. An unusual option but you already have a host of the correct length and might find using AA's in your SureFire appealing. I've used this configuration a lot and it works great.
As an aside, I have a difficult time imagining SureFire suggesting that a G3 can operate a P60?? There is pretty much no way to get the correct voltage without using a 1-cell spacer in the body tube. The P90 incan lamp assembly can run on either 3 CR123 lithium primaries of 2 17500 Lithium Ion rechageable cells, both have the correct voltage.
The SureFire 9P/G3/C3 are very practical lengths, permitting voltage configurations that enable both incan and LED configurations, and containing enough watt-hours for substantial runtimes. The OP can add the Malkoff M60L LED drop-in to his G3 and have a great light.:thumbsup: