You should put a PAC4 on the M16. That would be an awesome addon. The PAC4's we used in the Iraqi Freedom War were pretty damn usefull. Without NVG's you couldn't see anything different, but with the NVG's on, you can see the IR beam from the PAC4, which made it nice because you didn't have to aim down the sight. You could shoot it from the hip and still hit your target with ease. (Minus the boresighting. That was a little bit of a pain.) It's almost impossible to aim down the sights with NVG's on anyway.
Just a thought.