93 gc 4.0 motor mod questions

So I have read all the varies mods that you can do to the gc 4.0 for more hp. such as the newer style intake manifold , cold air intake , throttle body spacer etc. I plan on buying a newer boat this spring that will weigh about 3000 lbs which is within the limits of towing stock , but I face a couple serious hills in the spring fishing so Im trying to get a little extra power . what would be the list of the most benefical mods i can do in order of benefit and the expected power gains . I have the gc 4.0 , 42re tranny , 3.55 gearing