While Glocks are truely outstanding handguns right out of the box, there are many things that can be easily and inexpensively done to make them handle and function better. These mods do not interfere with holstering, reliable operation and handling in any way. And I carry IWB and OWB often. The expense to replace/install these parts is very low for the most part except for the night sights. And all were done by me and are relatively easy and quick to do for anyone with even basic mechanical skills.
G19
Trigicon night sights
3.5 connector
Wolff trigger springs and striker spring
Glock extended magazine release
Extended slide stop lever
Extended slide lock/release
SS guide rod
Grip backstrap plug
Pearce plus one mag extention
G26
XS Big Dot night sights
Glock extended magazine release
Extended slide stop lever
Extended slide lock/release
Grip backstrap plug
Pearce plus one mag extention
As far as the issue of legal modifications to a handgun somehow making prosecution more likely in the event of a legal shooting, well that is just another intertnet myth........lets see the news articles about DA's prosecuting gun owners for using legally modified handguns when the use of the gun was justified otherwise. With many 100's of thousands of Glocks in public hands we certainly would be seeing these cases in the liberal media. I did a Goggle search and found no cases because there are none to be found. If someone has one I would love to see it.