took both drain plugs out of the bottom of the stock muffler and yes it makes a difference... i live in the desert so there is never a concern about water. only other mod i did was to add a 13 tooth sprocket and thats its... later Jim...

 

i was woundering what kind of improvement you noticed with taking the bolts out....

 

ive gone one step better today i drilled half inch whole thru the inside of the muffler.. with a long drill bit i was able to drill thru two chambers straight into the muffler and i put the furthest most plug back in and left the back one out still it sound nice and the entire powerband comes on faster. Jim.