You might improve performance by changing the prop. It depends on what you are looking to do. If you are wanting more speed you can do that, but you'll likely sacrifice the bite you get. I've seen boats that were fast but bogged down if you put a skier behind them. The top end was better but the boat was slower off the start. It's a compromise in the long run between power and speed. You have to decide what you want. A pontoon boat is not exactly designed for great speed. In the South we call 'em party barges, not exactly a name that invokes the image of speed. The article above shows how to test to find a prop that does what you want. There is unfortunately, no prop that improves both speed and power for the most part, unless you have a tiny little prop more suitable for a trolling motor. That's the only situation where I think you can improve both.
Unless your motor needs some work, changing your prop will be a trade-off.