Need Help With My O/r X Pipe!!

[ThatGuyMarin]

Hello! New here and need some help. I have 2012 5.0 and just installed UPR o/r x pipe. Having roush ab's on I wanted it louder with is why I went catless. After the tough install, (due to unbolting in a very awkward area using jackstands) it sounded great and I really loved the sound. But after about an hour I started hearing a rattling noise like some bolts became loose. I took it to my mechanic and he made sure everything was tight and on nice. The set up sounded good and nothing felt wrong. No rattling or anything. After some hard pulls and a 2 hour road trip the rattling came back, cant figure out if it is just your typical o/f x pipe or the clamps and/or bolts are on right. Any Ideas? Thanks. Here is a clip of the sound