Greetings....I am a Newbie here. LOVE THIS SITE! I have the quite baffles on my '07 Mastiff with V&H Big Radius pipes...which now has 500 miles on it. I did not put a db meter on it, and in my opinion they did reduce the SOUND LEVEL some but not dramatically, but they did drop the SOUND TONE considerably and took away the annoying hollow tube/popping sound the stock V&H pipes have. As per instructions of the owner of Big City Thunder (Jim Maybeck..one of the nicest guys you will ever talk with), I am running them and all of the stock V&H baffles I could fit in...and the combo does work quite well. He even custom made me two long fastening bolts to put in the stock baffles to see if that would reduce the tone even more. I live by the 16th hole of a golf course, and I did not want to disturb the natives. I am very happy with the set-up.