RE: help with sound...
 

I have a similar problem, does it rattle mostly when the tranny shifts gears? mine does everytime it shifts into another gear, at the start of the gear the cat and arospeed mid section pipe rattle but it only lasts for a couple seconds unless i press the pedal more. my bro in law has recommended me to re torque ALL nuts and bolts and reapply gaskets making sure theyre in the correct position, cus he told me something about that if the pipes arent lined(bolted) up as straight as possible then pressure could be escaping causing the pipes to rattle. the weird thing is that all this rattling started when i installled my arospeed mid section pipe, back then i had my headers, cat,stock mid section pipe,rear section flowmaster and no rattling but i added the "high performance" arospeed pipe and all the trouble started.

RE: help with sound...
 

the resonator, isnt that the silencer?
man i put my silencer last week on my other rear section apc exhaust and it only got worse and with my apc rear section i noticed hp loss, so i put my flowmaster back in and damn! its runs like a beast and doesnt rattle as much but still rattles. im just glad its running like a beast.[8D]