Silencer...
You can use the silencer that comes with the engine...
Well... but it's a little bit heavy...
I don't know what kind of muffler everibody is using, but if I were you, I'd stick the original muffler.
(Ahh, Marcelo Colombo also uses the original muffler... It's just that you'll have to do a lot of drilling, cutting... look at the manual's pictures and you'll understand what I'm talking about)
Fabio Quintal