x-pipe in 3.0
 

Has anyone added an x-pipe in place of the resonator? If so, how is the sound in the cabin at cruising speeds? Also, what size diameter did you use? I'm guessing 2.5"

I tried searching and only found info in the X5 forum.

Thanks.

Will that cause emissions issues?

I don't believe so. The resonator is only there for sound muffling. As long as you don't mess with the cat converter and/or 02 sensor you should be fine from a "smog" standpoint.