The easiest way is to remove fuses 146 and 147 (5A fuses) after you have stopped the car in Sport + mode. Don"t bother....... the result of leaving open flaps equal to 0 ...in Efficient and Sport mode the exhaust will be silent....our enemy is OPF.
My conclusion: slip on aftermarket exhaust (to be legal). Something like Remus, Lightweight and soon Akrapovic.
Now I see...you are from Canada and you dont,t have OPF installed on the car.
)))
I will send you somme pictures with the steps to remouve that fuses