My trigger pull was 3.5# on my Shadow 2 SAO.
I changed the trigger return spring for a lighter one and added a 13# hammer spring.
This reduced my trigger pull to a crisp and predictable 2.5#.
I also put on a red dot and change to G-10 grips from Cool Hand Gear.
This gun is an absolute tack driver and I have replaced my S&W 52 with it, it shoots that good.