I'll join in i guess................i put my harley exhaust on (long chrome cylinder) it was still to damn loud, changed the center to a restricted type, this helped, i then welded the loop part of the exhaust from a rhino in and it helped, i then added dynamat to the underside of the center console for noise reduction this helped too.
i have dynamat still in the box it came in...havent taken the time to install. from what i read from other forums it greatly helps with noise and heat should be installing it now instead of being on computer. as far as muffler i still run stock but if i put cdi box on i will go with speed werxs for both. they were great to work with when i purchased a clutch kit.