Performance/free(er) flowing exhaust, sure. Muffler delete, especially on an X5? Umm, that would be NO, IMO.
I have not heard an X5 that didn't have a muffler, but of the cars I have heard, it's just too damn loud. Track and super aggressive looking cars (you know, the ones with raised white lettering on the tires
) play the part better, but still wayyyy to loud for my tastes.
Totally out of place on an X5. Again, IMO of course.