Currently, as it stands you can put suppressors on nearly every weapon. You cannot however find any subsonic ammo for 90% of those weapons. It would be nice to get some 5.56mm, 6.5mm, 7.62mm and other realistic sub-sonic calibers. Arma 2 had sub-sonic ammo for assault rifles, why not arma 3.
The asp-1 kir has subsonic ammo, we need more!