Benelli M2 20ga is the best 20ga on the market today in my opinion
Won't get any arguments from me on that statement. I still think the needs of a turkey gun are so vastly different from wingshooting that I would try to get 2 guns for the $1600 budget. I think if you shop around, I think you could get a black m2 and a 870 in budget.
Both will last a lifetime unless you abuse them.