I am not a 1911 snob. I like Glocks and recognize them as a very good firearm. "Ugly, and no soul!" But they work! For a 1911 shooter, Glocks tend to shoot high. A grip reduction will cure that, and provide a better feel for the gun. The third picture in the frame shows the difference between two Second Generation guns. One a Model 23 and the stock one, and Model 19. In reducing the frame, the back strap is cut straight, and the frame rounded. Material is removed from the rear grip to help reduce the pressure felt on the web of your hand and thumb knuckle. The magazine release area is also cut, to allow for positive engagement. The trigger area is cut to allow the trigger finger higher and more free access to the trigger. The trigger guard is rounded for carry use, and because it just looks better. The magazine well is opened up a little more and the frame is either smoothed or stippled for grip. It is then coated with a special finish.
Additionally, for a carry gun, the trigger on the Glock is replaced. I do not care for the spongy trigger on a standard Glock. The stacking take-up, break, reset, etc... I prefer the action of a revolver, even for speed shooting. It is a longer stroke, that allows for sight alignment, right up to the time the trigger breaks. The Glock can simulate the action, somewhat. By the addition of the NY Trigger, and a 3.5lb disconnector, this becomes an even better carry gun. The trigger becomes consistent, smooth, and breaks clean. Reset is nominal, and shootability seems to improve. My opinion!