What does your gun say about you?
Defensive firearms are very personal. Some people prefer semi-automatics, some revolvers for concealed carry. For home defense, some people like handguns, carbines or shotguns. Grip size, trigger weight and other factors can be altered to help you operate the firearm more effectively. Upgrades to make the firearm more effective for the user are great add ons, but where do we draw the line for aftermarket accessories?
Jeff Bloovman of Armed Dynamics likens the firearm to a character in court. His belief is that if your firearm is modified with something unnecessarily aggressive, it can be detrimental to your case if you have to go to court. For instance, an officer involved shooting in Mesa, Arizona (article here) showed how big a problem you can have if you have a profane or unnecessary aftermarket part can be used against you in court. Specifically, the replaced dust cover on the AR-15 the officer (with a profane, violent message) caused the officer to have to defend his actions based on the perception that the accessory reflected his mental state.
Some things that may cause a "jury of your peers" to view you are overly aggressive are: logos depicting death and destruction (punisher, grim reaper), logos that lump you into a group of potentially unsavory or untrained people (molon labe, 3%) and accessories that use profane language. None of these items by themselves are what the case is likely to be based on, but how much time will your attorney need to explain this to the jury? How will the jury view your actions (through the lens of the prosecution and defenses arguments) if they have seen something that paints you as violent?
We need to be careful in what we are communicating through our guns. What is something we see as just a fun add-on may be perceived different in a court of law.