The prop is one of those things that will only be a problem once you get to a certain weight. I would just pay attention to how the engine runs when...
I changed mine to the 15.5x15 this spring because of the added weight. That speed/surf prop felt like it was making the engine work incredibly hard....
As someone adding a surf pipe and heater to my 21 Makai I would highly recommend getting it done from factory. I kick myself for not getting them on...