I installed a set of Monster Baffles on my 09 Train with Big Radius 2's. I think they sound awesome, neighbors might disagree. I wouldn't mind trying the quiet baffles they sell. Just to see what those sound like. But, installing cams made a huge difference in the sound. I can't comment on the horsepower because I did a bunch of stuff at once. I do know that the PC-V from Fuel Moto , the woods cams, BCT baffles, Evo 30T motor sprocket, SE clutch spring, Baisley oil pressure spring, made a hell of a difference.