Sticking with 16.5s will give you very few options for tires at all, let alone in such a small size. I would look around local shops just to see what you can even still get these days and pick whatever you can afford. Ordering online almost always costs more than buying in store when you account for mount/ balance. Last I knew BFG, Cooper and Goodyear still offer 16.5s I just don't know how small they go.