I recently purchased a 2005 17.5 alaskan, 53" with a yamaha 115 2s. I'm new to outboard jets, but it seems to be a great boat. It will do 35mph with my son and me in it. It has a aluminum 3 blade impeller on it, would it be worth putting a stainless 4 blade on it? Any input on my new boat would be great, thanks.