Weapon Attachments

Silencer

Silencers drop weapon damage by a fair amount, but they stop the sound of your attacks from alerting people over a wide area. If you take the time to line up headshots against unarmored foes, this lets you assassinate targets in relative safety. There is still some noise, but it’s not enough to trigger instant alarms unless you’re really close to someone when you fire.

You can also lure guards away from their positions. Use a silenced weapon to shoot an out-of-the-way wall or object. The sound is minor, so a guard may go to investigate without being alerted; they’ll only be suspicious. Ambush them from behind, knock them out, and drag their bodies away from that spot. This can be repeated to lure multiple enemies to the same ambush point.

Laser

These mods upgrade a weapon’s aim, making them easier to use. You get more headshots, waste less ammunition, and can win fights that much faster. All of your favorite weapons should be augmented with a laser as long as you can find one. They’re normally hidden in weapon storage closets. 

Holosight

These reduce recoil and raise the accuracy of a weapon by a modest margin. They’re extremely powerful, and should be placed on your favorite medium- or long-range weapons. You can’t have both a Holosight and a Scope at the same time, so the choice has to be for active firefights (Holosights are way better here) or sniping (take the Scope).

Scope

Scopes make it a bit harder to use a weapon during an active battle, but they ensure extremely high accuracy at long range. If you want a weapon for sniping purposes, this is the mod that you need the most.