I can't answer the exact question that you are asking because I don't have a YS 45 but I don't see why a MCM wouldn't work great on one.....I just got done putting a MCM on an OS .46fx on my CG EXT 330 and it is great and really brought the engine to life....I was using a tower muffler but it didn't compare to the performance that I am getting with the MCM.....I haven't tached it yet but with a 12.25x3.75 APC it hovers at barely over 1/4 throttle and pulls out of hover like a rocket....I think the Mousse can would work great with a YS the only thing I would say is that you may have to move your battery back a little bit if you plan on putting this on the CG Extreme because I think the YS is a little heavier than an OS.....just my .02 cents