the stock trigger spring is about 5lb, some places list it as 5.5lb. a coil trigger spring design, like the stock spring, is stretched when the trigger bar and trigger are in the forward position. therefore as the spring tries to retract it is actually exerting a force that "pulls" the trigger bar to the rear. when you use a heavier weight spring it adds more pull to the trigger's rear movement which results in a slightly lighter pull.
if you reduce the weight of the striker spring, which pushes the trigger bar forward, you will get an even lighter trigger pull. my personal preference is that reducing the striker spring and increasing the trigger spring weights results in a trigger pull that is way too light. some people like it for competition but i prefer just the 6lb trigger spring.
when you add the reduced power striker safety spring, it allows the safety block/plunger to be activated by the trigger bar much more easily which also results in a smoother trigger pull. now that you've done the polish job you may notice a small "hump" in your trigger about 1/8th of an inch into the pull. that happens when the trigger bar makes contact with the striker safety. the next 1/4 inch or so of travel before you get to the "break" is called the pre-travel or "take up" which is what will be lightened by adding the 6lb trigger spring and/or reduced power striker spring. the actual "break", when the striker releases forward, can be lightened by adding a 3.5lb-5.0lb connector. each brand and weight of connector gives a different feel but i personally like the ghost ultimate 3.5lb connector myself. along with the lighter break you will also lose some of that "crispness" in the break, but i think with the ghost connector it is minimal and well worth the increased accuracy you will get.
if you've got $30 to spare pick up
this kit and see how you like it. if you absolutely hate it either return to ghost or you will not likely have any problems selling in the classifieds.