Reduced Signature is honestly up there with Siege Ready and Engineering Kit/Fortified for me.

It is just so damn good honestly. You don't even need suppressed weapons to have it be truly useful. See that War Strider on the objective you don't wanna agro? just sneak around/behind it. Giant patrol of the worst kind coming straight for you? Go prone and let them walk past. This passive honestly has so much utility on its own that does not require a full stealth build. Wanna meme as a suicide diver? grab a bomb pack and sneak into a heavy base and go kaboom! This passive is easily S tier for me.