The smooth faced trigger on the compact & sub-compact Glocks is one of my favorite..
Also putting an over travel stop in the trigger housing of my G17L is another..
I also have the 3.5 Connectors in my Glocks.. Scherer & LWD..
25 Cent Trigger Job is also something I've done to my Competition Gun but not my carry..
I have also added fiber optic front sights to both my G17L & G26..