I would either replace the trigger or tune the existing one. It is the first thing I do to a new gun. For me a heavy trigger distracts me while trying to hold the crosshairs on target. A tuned trigger set in the 2lb range allows me to focus on the target and sight alignment while squeezing the trigger.

I agree with jim_k, a new trigger will not make the gun shoot any better, but in my case I does make me a better shooter.