I have the Bush, so I can't comment on the forward scope mount, but the rest of the rifle is the same. I may add the forward mount later, and word-of-mouth is that the Aimpoint is the best choice, using their own single-point mount, although there is a very interesting post on using the
Thompson Center 2.5-7x28 Illuminated Reticle Recoilproof / Waterproof Pistol Scope at http://hometown.aol.com/zoomii97/M1A-ScoutRifle.html
I was pretty much staggered the first time I shot it and was getting 1-3/8" 100 yd 3-shot groups using Federal's economical Am. Eagle 150gr HPBTs. This is with no bedding, stock trigger & sights, no NM mods at all. (The prior owner was getting moa groups with a scope and 168gr MK-HPBT handloads.) The 1:11 twist non-chrome-lined barrel is MUCH more accurate than most of the standards. With a scope and a few mods I expect it will only improve.
It also handles very nicely due to the weight centralization and short barrel. I think you'd really like it.
I know of NO aftermarket trigger groups, but you do not need one. Fulton will stone the trigger to a clean ~ 4.5# for about $35 -- that is all you need.
Re: the second post, no M1A or Garand-type actions have free-floated barrels. Kinda hard to do with any kind of a gas system there, especially since it has to attach to the forearm. If you want a floated barrel, get a bolt gun, or a different type of action system.