Mufflers for powertoys are tuned to the engines usually, unlike cars where they aren't really performance specific.
And if you think thats bad..
My 701cc Superjet, the "Type B" exhaust costs 600$ brand new.
My 927cc Superjet, I have a "WDK wet exhaust" thats costs 900$ brand new
And I need to purchase a new exhaust this coming year, a "Powerfactor dry pipe exhaust
, which costs 1100$ brand new.