So I've noticed only when my car is idling, that there is subtle pops coming from my exhaust. My brothers XRT doesn't do it and we both have x force exhausts. Mine is BF and only other mod is 60lb injectors and (suspected of the shelf tune) from previous owner. I figured it'd be a better idea to record a video, so here it is. Try listening with good quality headphones at mid level, were it's most noticeable. I don't think it's normal and no issues under higher revs. XR6 turbo exhaust noise: http://youtu.be/C-VNgv0lRQY Cheers Ed