I think its a bit more than 10db, from what i've heard from the manufacturer it makes the noise closer to stock.
buell exhaust, to loudjsw07, i unwrapped and installed the quiet insert i had laying around here.
and to tell you the truth, you are not going to be happy with the result.
it is a tiny bit more quiet then without (overall volume), although there is less bass in it, which will bring the db level down to about 100-110db.
people would say: "look at that cool pastor, let's go to church and meet him"Imagine me pulling up to the church almost everyday with that pipe on my bike!