The Wilson trigger bar does three things. One, it is made of a harder material than the factory, so it makes for a smoother and longer lasting DA trigger job. Two, it has and over travel stop that reduces over travel and therefore reset distance. Three, it pulls the hammer back further in DA than a stock trigger bar and therefore gives more energy in the first DA hammer strike.
It is a really great part and one that I help with from the very start, basically my idea. It was a replacement of the Speed Bump Trigger and a better option than an over travel stop on the trigger.