One has only to thumb through one of the gun parts catalogs to see all of the cool stuff that can be added to today's self-defense guns. While I am happy to see so many accessories available, I have to say that they are often a temptation to wander off down a very rocky road.
When I started in law enforcement, nearly all of us carried revolvers. It was not uncommon for a fellow to have the action and trigger pull slicked up, and it was very common to see officers who had changed the stocks in order to facilitate a better shooting grip. However, most of us were smart enough to have a professional gunsmith do the action jobs on our revolvers. But times have changed. Nowadays, folks are tempted to order a bunch of aftermarket parts and try to fit them themselves.
Long ago, I adhered to the philosophy of one of the movie heroes when he said, “A man ought to know his limitations.” Although it pains me to admit it, I have found that I am not any part of a gunsmith, and my attempts to work on guns usually has very negative results. In addition, I have found that the most highly modified firearm available will still not make me shoot like Jerry Miculek. Those facts have made me take a very hard and realistic look at this business of modifying a firearm, especially one designated for personal defense.
A defensive firearm should have a good trigger, sights that you can pick up quickly and stocks that fit your hand. Beyond that, any other modification should be done only after long thought and the realization of a specific need. A person should be extremely honest with himself when it comes to his own ability to perform any modifications. Yes, the work of a professional gunsmith is expensive, but we have to keep in mind that our lives could depend upon that gun and it would be ever so nice if it actually works like it is supposed to when the balloon goes up.
Over the years, the most firearms that I have seen malfunction have been those that were subjected to a dose of home gunsmithing. These were usually guns that had been modified or accessorized because the owner thought it would make them look cool. These are usually the same folks who cuss the manufacturer when their home-cobbled defense gun malfunctions repeatedly.
There is also the question of whether or not a highly modified firearm might be used against you in court. Frankly, I am not qualified to answer that question and suggest that you discuss the matter with a criminal defense attorney who is familiar with the issue in your area. Internet chat rooms is probably not a good place to get that sort of legal advice.
My own experiences have shown me that I can survive with a defensive firearm that is pretty much in the same shape as when it came from the manufacturer. I suspect that this is also true for most shooters. Even a properly modified gun will only improve our scores to a certain extent and it will not make up for our lack of skill or training.
So, in the end, I am not against modifying the defensive firearm. But I do suggest that modifications should be made only after long thought, and it is really smart to involve a professional gunsmith in those thoughts and discussions.
You are still the one who is ultimately responsible for your own safety. That holds true even if you have modified and accessorized your defense gun to the point where it is no longer reliable.