I want to order a performance(Biturbo or Da Vinci?) exhaust for my moped to speed it up another notch. What do people recommend? I have a 1977 Bianchi Snark. My muffler now is a two-piece muffler on the right side of the bike. The bike uses a standard Minarelli V1 engine w/ a 14.12 Dellorto carburator. I think Da Vinci is what I need? Or can I use a Biturbo?