The best rim size is the smallest that fits over the brake rotors. I'd stick with 15" rims even when you get 17" later. Sell the 16's as you say they are heavier. If you have tires already for the 15" rims, great. If not or when it comes time to replace, Falkin Azenis Sport is what you want if you want to stay in street tire class. They are cheap and great for dry grip.
