Pork_Chop, You left out specifically what the G20's intended purpose is.
I have a G20 that I have put in an extended slide release, a slug plug, Truglo Mepro Adjustable sights, a 22 lb. guiderod spring, LWD 5.15 tactical barrel, A LWD 6 " ported barrel, a 3.5 lb. connector, and a titanium safety plunger. I'm also planning grip reduction and texturing. I shoot only 200 gr. bullets at 1325 fps. I'm over 50 and don't run anymore. Hollow points for two legged creatures and FMJs for four legged creatures. 40% of what I shoot will hopefully hit meat. I made this gun to kill, nothing less. I don't go to the range as much as the other guys. If I shoot for fun, it is usually with a .22 auto while plinking. I grew up in the swamps of Louisiana, so my priorities may be a little different.
The point that I am trying to make is that I customized this gun for it's intended purpose, which I had to select. I whole heartily agree with Oceanbob on running the gun stock for awhile before you do anything to "customize" it, if nothing else, just to "FEEL" it. Then you can answer the one question that these guys or anyone else can't answer for you;
"What do I want this gun to do for me"? Once you answer that, then their selected advice becomes more valuable. Actually, in a way, my gun was built by them, collectively.