Contact the manufacturer before you drill out the rivets.... It "should" be a simple drill out rivet, remove packing, re-rivet.... BUT how many times has something so simple turned into a nightmare? Maybe they sell a kit like I got from Brock's when I sent my CT out for ceramic coating.
On a side note, almost every aftermarket bike exhaust I have ever used seemed to get louder over time when the packing burns away. Looks like a nice exhaust, I checked their site. Good Luck
2015 30th Anniversary Edition 14R #250-> Brock's CT Ceramic Coated, Ivan's ECU Flash V2 & Map, Block off plates, HM Strain gauge quickshifter, GPR Damper, Spiegler lines, Muzzy's Sliders, Pazzo levers, Rizoma Next Fluid Tanks, DDM Ultra 5500K HID's Low & Hi, DB Windscreen, Cox Radiator guard, gold titanium bolts... too many to list at this point