Save your hearing? That's a pretty ironic statement, not even considering its on a car audio forum.
You are correct silencers are not illegal, but they are very difficult for the average person to get legally. While they are obtainable, its a more thorough process than simply paying a couple fees. Including a background check, and application with the ATF. Im guessing this will include giving a reason why you require a silencer as a private citizen. Im confident they, if approached with the idea you want to be able to shoot at home invaders without risking hearing damage, would conclude that the sound of the firearm is a useful tool in a home invasion. Scaring off the intruder, and alerting neighbors or family members would be 2 examples.
The Quake mentality is thinking this is a game where you will WANT to confront the intruder. If faced with such a situation, most people would rather scare the intruder away rather than risk an actual confrontation. Are we trying to protect our home and our family, or just kill the bastard for daring to enter your home?