I ordered the Apex Flat Faced trigger kit 100-054
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and installed it myself. It took me a total of about an hour and a half, excluding the first trip to the range where I found I was getting light strikes and needed to make adjustments to the sear actuation loop on the trigger bar.
This is the fifth Apex kit I have installed and it went well. I now have the proper tools. My first experience was successful but took more time and was somewhat frustrating as the You Tube video instructions were not very good and I did not have some of the tools that make the job easier/faster. However, a gunsmith will probably charge a minimum of $50 to do it, and probably closer to $100.
I had previously spent time polishing the trigger bar and the striker block channel, the feed ramp and chamber, the extractor, and the center rib on the bottom of the slide. I also lightly polished the inside of the slide rail grooves. All that took an hour. I also shortened the beaver tail at the top of the grip. I find it too long for my concealed carry.
Mass produced guns are a compromise in finish quality and features vs. price. There are two camps in the gun modification debate.
One is that you should not do it because there may be negative legal ramifications if a prosecutor (criminal trial) or opposing attorney (civil trial) discovers your modifications and tries to use them against you. If you lightened your trigger and then fired unintentionally and hurt someone, you could be in trouble. However, if you didn't adjust your trigger and negligently hurt someone, you're still going to be in trouble.
I am in the second camp. If you (actually, your attorney) can reasonably articulate that you made changes to your mass produced gun to make it a better tool to defend yourself, the opposing argument can be defeated--if it was a good shoot in the first place and if your follow-up actions and statements have not hurt your case. IOW, when I make my gun more accurate with an improved trigger and easier to control with a stippled grip, I make my success in defending myself more probable. If I needed to defend myself and nailed the perp only (good shoot), I feel confident I can overcome the "modification" attack. Documented defensive gun training is a big help in such a situation, especially if it was with a gun similar to the one you eventually used to defend yourself.
It is interesting that with the variety of customizations and aftermarket improvements for the AR platform that people never seem to mention this same issue. If one uses a non-stock carbine or shotgun to defend oneself, could this still be an issue? If I was a gun-ignorant prosecutor, sure. Yet this argument doesn't seem to stop anyone from modifying a long gun.
The same negative camp will also say you should use the same ammo as your local law enforcement. However, many departments buy based on price with performance a secondary characteristic, or their terminal performance standards while adequate may not be top notch. The best self defense ammo may not be affordable for law enforcement, but does that mean you are not entitled to use it? I feel I can articulate why I chose it. [I worked for Barnes Bullets and know their bullets' terminal performance and ammunition quality intimately.]
In the remote chance that I ever am involved in a self defense shooting and end up in court (even less likely), having the best ammo, gun and training should overcome the opposition casting dispersion at you. You need a competent, gun savvy attorney who can ask the right questions and rebut opposing counsel effectively.
IMO, it is more important to first win the fight, and I try to give myself every advantage to do that.