Another consideration: should you, God forbid, end up shooting someone in self defense, you will almost certainly be sued by some family member with a sleazy attorney. One of the first things they look for is an altered trigger pull, which allows the charge that you inadvertently pulled the lighter trigger which resulted in liability for injury or wrongful death. Your defense of "hell no, I meant to kill the SOB" may not go over in certain states, although here in East Tennessee and in parts of Texas as well you might get applause from the jury. Lighter triggers are great for target shooting, but NOT for self defense where fear, adrenaline and tunnel vision will fire the weapon for you if you aren't careful. The R9 is the purest example of a close range self defense carry pistol, and should be left alone. Just my opinion.
John