The bells and whistles are a lot of fun,and may actually increase the effectiveness of the weapon, which is tremendous as is.
But how about increasing YOUR effectiveness?
Put off buying those heat seeking 000 buck loads and spend some money on practice ammo and range time.Trust me, yiou'll be better off.
Then after you've become the deadliest shotgunner this side of Quantico, you'll have a better idea of what your shotgun needs for improved performance.
BTW, my HD 870 has darn near all the tweaks, but I knew how to shoot it before I reached for a catalog.
I did a thread on HD training here a while back you still might be able to access. IMO, there's some good input there about this topic,and not just from me...