I've tried all different kinds of tacticool stuff on my 500, ranging from about 5 different stocks, pistol grips, red-dots, lights, shell holders and one think I've found out is that if you actually shoot it most of it's uncomfortable and you can't hit jack with it.
Now the only thing "extra" I keep for my 500 is the 28" barrel for trap/hunting. I gotta go with Brent on this one...I need nothing more than my plain jane 500. It's sporting a new mag tube and barrel as bent the old ones when it jumped off the 4-wheeler and under the tires.
But at least I get to add new wear marks.