[Wu Jen]

They both do the same thing but the only thing they list as not stacking with is a smartlink system.

One is a sight allowing you to put a dot/crosshair on where you bullet goes, the other is a laser visible through the sight to ensure that it is lined up.

By RAW it looks like they would stack, by RAI its a huge bonus (if your including wireless) +2 die to Attack Tests and +2 to Accuracy and may be a bit much?

[Michael Chandra]

RAI I would disallow it, yeah.

[RickDeckard]

Since they do the same thing and don't compliment one another I think you have to choose which one you rely on for the shot.