Hov333 to tell you the truth cut off the muffler and the silencer can all at once.
There is no noticable sound in the cabin, especially not at driving speeds. Sounds stock inside. There is absolutely no droning or loss of torque.
I am actually gonna remove the Y resonator and run straight pipes from the cats. I got too used to the sound and wanna see if i like the straight pipe growl.
Another alternative is the electronic muffler valve cutout. It actually might be a better option as you can alternate between stock and beast sound with a flick of the switch.
E39 540i Sport