I've tried researching to the best of my ability, but have come to a dead end. I'm interested in buying a DBAL, probably an I2 but would also want IR illumination. Would I be better off getting an IR head (KM1) for my Surefire M300, or just getting an DBAL A3? I'm not sure which would be best. This is not for any kind of official use, I've just got the NV bug and want an additional range toy.

The I2 and ATPIAL-C have laser illumination, which means they are maxed out at .7mW. that will get you about 100yds on a good night.

Surefire are LED, meaning you could get better performance,but you have a small visual signature downrange of the LED, although small.

Since I hunt a lot I use LED.

I was just looking into this today. The i2 illuminator (single spectrum) is the same as the a3. Here are some videos comparing the a3 to others, there is a comparison to a surefire vampire at 2:30

https://www.youtube.com/watch?v=ooUqw6d-_rc

Between the A3 and the i2 single spectrum, the real question is if the cost difference between those two (about $300 or so) is worth having a visible laser for zeroing. I personally don't think it's worth it but I'm sure plenty of others here would not agree with that. Either one you're going to want to pair it with some form of IR weapon light for better illumination past 75 yards.

Personally I would go with i2 single spectrum for about $600 and then snag your choice of surefire IR light and use a dual switch.

All of that said, when you catch them on sale, you can solve all the problems in one unit with the D2 for about the same cost if you can get over how chunky it is.

The problem I have with pairing a Surefire is the white light output on them. Very poor output compared to normal white lights. I want a 600+ lumen white light, IR, and takes a dual pressure switch to run both the DBAL and flashlight.

If you dont care about having a very low IR signature skip the i2 9007/A3 and go with a D2. It cost the same as the A3, but the illuminator is good past 500 meters plus. The 9007, A3, or APTIAL-C illuminators are only good to @ 75 meters in an urban area and maybe 100 meters in a very very dark area. I've ran a 9007 and a SureFire 622V for white light and additional IR light if needed. It extended my IR range to @ 100 meters. The reason you'd want a powerful illuminator is not only to see a far distance in a open field, but also to punch through a lit area to see what's hiding in the shadows.