Looking at some exhaust options but can't decide. My options: 1. A 35mm tip on the stock exhaust (free) 2. YZ exhaust system 3. Dubach ATV exhaust (full system) Regarding Dubach exhausts, what is the main differences between the ATV pipes and the MX ones? Is there much of a performance increase with the ATV systems in comparison to the MX ones? There's one of these exhaust systems going cheap at the moment so I'm not sure whether I should get it or not. enticed by the fact it isn't loud. Also what is a 'step up' ? On a side note - if I change the tip of the stock exhaust to a 35mm should I have my jetting changed?