Audi S6 4.0 TFSI C7 quattro YOC: 2012 - 2018 Part: Cat-back Info: Resonated (quieter) with Titanium tips. Some 2016 and later models have an updated valve location on one rear silencer meaning the wiring loom needs extending to accommodate. tailpipe design: Quad 100mm GT100 pipe diameter: 70mm /2,76inch EC-approved: No Race system: No Valvesonic: Yes Part no.: SSXAU446