If you have a silencer, you don't show up on the map. You are also more accurate since the ACR has no recoil and the UMP and SCAR have minimal recoil. Steady Aim allows me to just walk into a room and shoot and kill everyone as I don't need to aim down the site. Just turn the corner and press the trigger as the gun doesn't recoil and accuracy improves with Steady Aim. Sub Base is the best place for this, as is Terminal.