+1 on checking the hanger bolts when it rattles. You would not believe the noise those washers can make if they aren't tight.

 

I had the exact same rattle you described
when I had the O/R H with my stingers.

I knew it was somewhere in the front,
probably where the H-pipe meets the collector.
Several months later, I put the stock H back
on for inspection, and the rattle is GONE!
So, it was probably bad fitment from Pypes,
or maybe bad installation by me.

I really miss the way the exhaust sounded
with the O/R H, I'm thinking of putting it
back on...

 

Installed my FRPP Stingers today. One rattles because the hanger elbow touches a bracket. I can wiggle the exhaust tip and duplicate the rattle. Pretty sure this is where it is coming from. Can't very well bend the elbow farther away. I think I can bend the bracket out of the way though.

 

i have a slight rattle when i hit the gas, say in 2nd gear at about 1500 rpm, but i think its just the deep sound resonating through the car.

 

i still have the nasty rattle with boomtubes, its a loud squeal at low speeds and random rattles at all rpm. im just going to take it to a different exhuast shop. i brought it back to the shop i had it welded at orginally, and they said "im sorry sir, we do not warrenty our work on 3rd party exhaust systems" ummm, ok, you cant put the thing on a hoist and inspect the hangers? geeze

 

So what happened here?