The reason I ask is i can get a good deal on a used hmf full exhaust. I have not been able to find any used duals and i cant pay 6-700 for new ones. So with the big 3, single vs duals are we just talking about 2-3 more hp? The only other thing i could ever see myself doing to my bike would be a stage 2 or 3 cam. Would a single really hold me back that much?