CSL exhaust "Rasp" ??

[Windowlicker]

Hi there,

Question is, which part of th eexhaust system is it that generates the raspy metallic noise
/ Is it the centre section, the backbox?
I like the noise, sounds quite rude, but would replacing the offending section with an aftermarket item, Miltek for example, retain the charcteristic noise but change it to a deeper sound, rather than being so tinny?
Thank ya, in advance.