My XKR exhaust pops a bit when I lift off. Gratifying as this obviously is in making me feel like I'm down with the kids, I'm wondering if it's actually meant to be doing it. I know what exhaust crackle is, and I know it's basically cosmetic on non-turbocharged engines. So is this a feature or a bug?

 

Mine did it slightly before I removed the resonators and installed an X pipe. Now it does it a bit more, and a bit louder.

 

I'm willing to bet fuse 19 is removed, if so it's nothing to worry about.

 

Fuse 19 is indeed removed.

I don't understand how having the outer tailpipes permanently open would affect this one way or the other.

 

I've never put any thought into it, I just know whenever I remove the fuse it pops on overrun.
As a way to prove the theory, reinstall the fuse and take it for a drive and see if it does the same thing.