Flat trigger is just a trigger shoe. Feels nice. Doesn't really do anything for the pull/feel.
Spring kit gets the pull weight down to a manageable weight. Unfortunately it doesn't do anything for the reset, which is quite long on this platform.
It is the best bang for the buck IMO.
You could look at the CZ Custom kit... it's on par with nice AR triggers, but is in the $250 ballpark.
I think the reset is ok, but I know you do a lot of comps.