Re: AR-15 style gun upgrades
I think every AR needs the following items.
1. Quality optics-EOTech, Aimpoint, Trijicon are all quality choices depending on what you want.
2. Quad rail for adding accessories.
3. Vertical grip. I know some don't like it but is makes the gun so much more maneuverable and stable.
4. Tactical flashlight and/or laser sight.
5. Quality BUIS (back up iron sights)
6. Quality mags
I would also add a bipod to the list but unless you are using it for hunting purposes, it really serves little purpose on a tactical carbine.