Tried it on a Manx Norton 500cc instead of original Mega and gives incredible results in terms of noise reduction, drastic, and needs almost no intervention on the carb. settings. Very good, simple, light, cheap and neat way to cope with nowadays drastic noise regulations of 105 dbs used on many circuits.
Yes, this was the only option that seemed to offer super-quiet operation for my Toro Z-Master 52" with a 25-HP Kohler Command engine. First, know that you have to buy the "innards" and the "outer" separately, and it adds up to a pretty expensive muffler! I do have a Sound Meter, and the sound level both before and after installation registered at 80 dbA measured from 20 feet at 45 degrees - but that doesn't really tell the story. The mower is so quiet now I can actually hear the fan on the engine whooshing air and the blades as they are cutting grass - THE DIFFERENCE IS PHENOMINAL! I bought the 1.5" size since that matched my mower exhaust and had a local muffler shop bend a U-pipe and I am very happy with the results - SUPER QUIET.