Same with me for the IS. I wish i kept the scorpion backbox i had I will be buying a magnaflow backbox now. Really like the sound from them even with the cat still on the car.

https://www.youtube.com/watch?v=VqjJOFHh8pc

https://www.youtube.com/watch?v=_hBhh4dYj-0

on a 328:

https://www.youtube.com/watch?v=hvWid6RCcJs