I have an '07 Xstar with the 8.1l and after consulting with OJ props, I switched out the stock prop (13x22) to an OJ 14.5x17.5. Its a great prop for hole shot and cruising. Your boat is slightly heavier so you could also consider the 14.5x15.5 which will have more low end pop but not as much high end. Do a search for Eric at OJ props and call him.
Previous - 2007 X-Star w/ 8.1l
Previous - 2007 X2 w/ MCX