There are always trade-offs:
A heavier trigger spring will help you pull the trigger easier. It will also make the reset sluggish.
A lighter striker spring probably has the biggest effect on reducing the trigger pull weight. It will also cause light primer strikes unless you also use a lightened striker and/or use soft primers exclusively (i.e Federal).
A lighter recoil spring will speed up the slide and reduce felt recoil (when used with light loads). Too light can lead to failure to go into battery. In extreme cases, the striker spring can overpower the recoil spring and pull it out of battery.
A connector just changes the geometry; probably your best bet for not negatively effecting reliability.
My plan for my new Gen 4 G34:
-connector (Taran, Zev V4, or Ghost Evo Elite)
-lighter firing pin safety spring
-stock trigger spring
-stock striker spring (or maybe a 5.0 lb)
-13-15 lb recoil spring