It is a little louder at idle, if u rev to about 3,000 out of gear sounds really mean, going down the road it has a window from 3,250 to 4,000 it gets the loudest then drops off at 4 and still sounds good, overall throatier and louder i really like it. I was going to video that dyno but they did it before i could get there. X-metal is awesome and so are their products.