Installed mine this weekend. In the city a little difference slightly louder, same pitch. On the highway you can hear the thing sucking air pretty good (going to check hose clamps). When passing on the highway everyone notices. Had to try it, at 5k the engine sounds completly different. I didn't think the intake would make suck a big change in sound but I am prety happy with it. I talked to a shop in St.Cloud about a custom cat-back and quoted me $200 when I showed him the Calmini set-up. Added benifit is they will adjust the tone to your liking while assembling it. I know where I'm going to get that done, but I have to graduate and get a real job first. I see all this as motivation.