I installed the Lionheart trigger in my SR45, see: https://gallowayprecision.com/ruger/sr45/lionheart-short-stroke-trigger-for-ruger-sr-pistols
It does shorten the pull with a slightly improved reset. I say "slightly" because the stock Ruger SR series of semi-autos are excellent so improving them is a challenge. I have the entire SR series, 9E, SR9C, SR40C, SR40 and SR45. Only the 45 has the Lionheart trigger as I saw no reason to change the triggers on the other SR's. I was at my range today testing loads for my Shield 9mm but also had some fun with the SR9C and SR40C. These SR guns are really terrific, soft shooting, accurate, crisp trigger break and reset, etc. I did, however, install Galloway's recoil spring, guide rod, striker spring and indicator rod in all my SR's. I also removed the magazine disconnect in all guns.
I measured the SR45 pull at 4.5 lbs. I did not have a trigger pull gauge when I installed the Lionheart trigger and the Galloway springs so I can't give a before vs. after measurement. Considering my other SR's are 4.5-5 lbs, I would assume the SR45 factory is 5 lbs.
SR40: 5
SR40C: 5
9E: 4.5
SR9C: 4.25