Hoony, i think the sx mufler cost about $250 from a ktm dealer, I dont think it is std though its a hardpart like the dude above said same for a 250 or 300, by chance it looks just like the one in the photo above. It made the bike a bit more snappy which i like seeing my last modern was a yz 250 2002. The sound is no too noisy but a nice note. The owner of the ktm shop said that it would make it a fun thing to ride, i also rejetted, but funny enough i prefer the mid strength powervalve spring.