I received a new muffler for my Saito 150 last week and switched engines in the CAP.
I took out the OS150 with a slimline pitts mufler and compared the weight with the Saito and new muffler. The difference was about six ounces. WHAT A DIFFERENCE THE SAITO MAKES IN LANDING!. No more wing tip stalls, cartwheels, etc.. The planes stalls perfectly for 3 point landings. The difference was night and day.