I thought it would significantly boost the noise level, but it didn't. At idle there's only the slightest difference from before the x-pipe (keeping in mind I've got a Supersprint exhaust). Still rather humble at idle. However, I did notice a decent increase in noise at WOT. Still not as loud as other "American Muscle" type V8's, but it does grab your attention:-) I don't have any sound clips of my X5, but there's plenty in the "Articles" section that sound similar. Hope this helps!