I bought my '07 Griso 1100 in Dec 2011. 4,500 miles on the odo. Original owner put on a Staintune. I never really liked the looks of the Staintune (the "can" style shape in general just doesn't look right to me on this bike) and it always had a little crack near the mounting bracket that I lived with. I never replaced the exhaust because I never really found an exhaust I liked the looks of enough to spend the money. I just waited.
Recently the crack became larger and the exhaust was clearly shot. So I shopped around and found this Agostini from AF1. This was the exhaust I was waiting for! The description stated more mid-range power and throttle response. Ladies and gentleman, believe the hype.
After 6 years and 15k miles on the Staintune, I can honestly say just installing this Ago slip-on in 30 minutes totally changed this motorcycle into a rocket ship. It comes in black too. http://www.af1racing.com/store/Scripts/prodView.asp?idProduct=61574