Have six rides (170 miles) on the 858, 4 of which I was running the Diamond s ti can. It is definitely louder than the same can I was running on my 21 Alpha 800 ctec. Pretty much a growling sound while riding. I think the standard for a lightweight, quiet can is the RPM ti can that I run on my 9R. So many people can't believe I am running a can on it because it is so close to stock sound levels.