Standard RRA LPK, trigger pull is 7-7.25 lb (single stage)
JP Trigger Spring + Disco Spring, RRA Hammer spring, trigger pull is 6-6.25 lb (single stage)
The question was, what would happen if you install the JP trigger and disconnector spring but kept the stock hammer spring for reliability? This was interesting because I wanted a reliable/SHTF setup but with as low of a pull as possible w/o resorting to unreliable lighter hammer springs, 2-stage triggers, or various mods to the hammer/trigger/receiver.
With the JP trigger and disconnector spring, and the stock hammer spring, the trigger pull was only reduced by about 1 lb to yield a 6-6.25 lb pull.
This test was conducted prior to and after the spring swap on the same lower (used for about 1000 rd). I didn't pay much money for the kits, and I bought an additional one for my other lower in case it worked out well.
I did run into something odd: The JP trigger spring is sort of offset where one leg is "bent". This causes the spring to shift towards one side (the safety selector side. Will the hammer spring leg rub against the trigger spring enough to the point where something breaks?
Other than that, here are the details, you decide if it is worth it:
1). $9-$10 kit
2). Reduces trigger pull by 1 lb to yield 6-6.25 lb
3). Should not affect reliability: stock hammer spring