Exhaust Rattling, can't find problem?

[YloDmonMSP]

Ok, here's the problem: I got my new 3" turbo-back installed and now I have a really bad metal on metal rattle. It can only be heard when slowing down in first when the exhaust is really vibrating. I can't hardly hear it with the windows up, so I've questioned if it is inside. I took it back to the muffler shop and took the guy for a test drive and he heard it also so they put it on the lift to see what it is rattling on. Guess what it is not even remotely close to anything that it could be rattling against and the guy even shook and banged on it and still wouldn't rattle, I asked if maybe something in the pipes and he said no but that it could be some engine noise with such large pipes making it echo. Has anyone else had this problem? Please give me some advice, this rattle is really annoying.

 

[DiscreetSpeed]

so i take it from your mods you dont have the engine mounts, when i installed mine, in 1st i could here it hittin something...and inly in first well found out it was the downpipe hittin the suspension frame underneath...since yours is bigger may be just that too...i really cant do anything about it though unless i get smaller piping....but that wont happen

 

[Daniel Young]

When I installed my downpipe it would only rattle through a hard turn. I found that it was hittin the deflector sheild . I just bent the sheild up a fudge and it sounds fine now.