I think it sounds AWESOME. Like a 911 Turbo with an exhaust. Of course the S65 sounds better, but I won't mind that exhaust note at all, especially if the car is lighter/looks better.
Current: AW/SO F10 M5 H&R Springs, 12mm/10mm Spacers
Sold:Imola Yellow RS4-KW V3, MTM 10mm spacers, Hotchkis rear sway bar, APR Stage 1, Milltek Catless, RNS-E, Euro RS4 Flat bottom Steering Wheel