Never had an S&W AR15 facsimile, only some of another brand, but would assume the S&Ws are quality guns and work quite well straight-out-of-the-box without modification, other than maybe a good quality scope sight with a simple reticle that requires no batteries, if you plan on shooting beyond a 100 yards.

Assuming good shooting technique using a benchrest, at least a couple of hundred rounds of good ammunition (not bulk junk) will tell you if you really need or want to do any modification. You may decide you like the gun as is. Some never discover how well these guns perform as they come from the factory.

"Upgrades" are sometimes improvements, but far too often they are nothing but changes only. These changes may actually amount to a "downgrade" when subjected to real use. Some shooters think that things like light triggers and high magnification scopes will make up for a lack of shooting skill, but they don't. A five pound factory trigger works fine if one will take the minimal time required to become accustomed to it.

The recoil associated with the .223/ 5.56 cartridge is quite mild and easily adapted to with a little shooting. Good luck-