I run a 2520Xl with 225 four on it. I put on the Permatrim and noticed greater response from the trim tabs (which, for me, negates the whole argument that Parker's factory tabs are too smal), better performance in terms of hole-shot and top end. Also, the boat corners better without ventilating the prop. I don't have super-accurate numbers, but I estimate upon observation that the boat is 1-2 mph faster at top end, same rpm; cruises better/faster (due to better running angle/trim set-up); and holds plane at lower speed (formerly dropped off around 18, now goes as low as 14 or so, depending on trim, water conditions). Installation wasn't too much fun due to limited instructions, template, but I'm happy with what it seems to have done for the boat.