I have the Trinity stage 5 on mine. It has a nice throaty note, but it is a bit louder than I would like. Not horrible, but you know its there. I have the silencer tube and spark arrestor installed. Without those it's unbearably loud.
Put one on mine, not a hp upgrade but with added deadner and spark arrestor throaty but not really bad in the cab. and looks a whole lot better then big ugly oem. Tryed with and without deadner pipe and arrestor, left both on but just my preference and LEO in the woods preference.