Only things I can think of are metal trigger guard, stronger tube spring, high visibility follower so you know your out. Personally I wouldn't want a sling for home defense. What type of barrel do you have? Personally I'd want Vent Rib with tritiu/fiber optic turkey sights on top but thats just what I like. If you have a bead, would you or would you not want a tritium bead? If you want ghost rings, once again I'd say tritium.
Ripe it apart clean it, maybe polish the internals.
Surefire foregrips are common as are the clamps that hold a light. I hate bite switches (pressure switches attached to a wire to the light) so I'd say one piece light system.
Three best stocks are knox recoil, speedfeed and foldover, depending on what you want, choice is up to you. That speedfeed if you don't want it will sell on the forum I imagine.
Oh snap just looked up what GGG was, set it up for a one point or take it off. Your in a good spot. You don't need to do anything but if you do have fun. If your a Yetti and you like the speed feed some of the recoiling slip on pads I believe fit over it.
If you want a sling, remington makes tube caps that have a swivel attachment. or you can loop it around where the tube and barrel connect. Personally only sling I'd consider would be a one point.