I put on a set of dual viper cans, standard length round, without any extra baffles. In the saddle I can hear them now, but no one else that I have asked thought they were loud. I bought them from flyNcycle, for ~200 total. I mated them to an old Kerker mid pipe. Sandy Spares in the UK has a similar set for about 300, if you don't have an extra mid pipe.