I just put an MCarbo trigger return spring in my recently inquired Mossberg SA 20. Man what a difference! The trigger wasn't awful, but it was pretty mushy and didn't have a clean break. This spring brought it down to rifle weight and it now has a much crisper break. I'm impressed. For under $20 it's a nice upgrade.
If you recall, I asked about the Kingslayer green circle dot sight a couple of months ago. I got that in last week and I really like it. The green doesn't flare like my red dots with my astigmatism. I have to sight it in and will pattern some TSS, but I think the gun has everything needed to be a fine turkey slayer.