I think some people have messed w/ it w/ various success. That's the downside of the QA, though. I hate to say it, but you probably should not have bought it if ya thought it was too heavy. I've dry fired the QAs a few times, and everytime I can tell it is too heavy.
U can play with the striker spring I suppose, but I wouldn't unless its gonna ONLY be a range gun.
And, the A/S makes a better range gun. I personally thing that the QA trigger is too heavy to have fun and bullseye shoot on paper, trying to get small groups.
I think it may be good for carry, though. As the trigger is a bit heavier.
I like the HK LEM triggers as well - but only on a carry gun. At the range, I thinks a bit harder to shoot very small groups/bullseyes with the LEM trigger - at least compared to a regular trigger (one could do it, I suppose, but it would take a lot of practice).
Basically, each trigger has its place.
As I love to go pop holes in paper, and am not satisfied if I just hit the target anywhere but the bullseye, I like the A/S.
But, IF U want the QA to eventually be a carry gun, don't mess w/ the spring...