I looked on the Leo Vince website. Looks like there is a weight savings of 4.05 lbs with the carbon version. Not exactly huge, but not bad considering it's just the muffler.
There is also a better sound clip on their website, but I'm still curious about the db.
'15 KTM 500 EXC / '13 BMW 1200 GSW / '05 Honda ST1300 / '04 Husqvarna TE510