Saw a photo of Cdelena's HKS exhaust system and noticed the extra chamber built in to the "Y" split before the two mufflers. The Honda stock exhaust also has a chamber hanging off it just before the "Y". I assume they are there to modify the resonant frequency of the exhaust system.

Can someone tell us for certain?

 

From my understanding of it you hit the nail on the head.

 

couldn't you cut this off or a certain amount off to get a louder sound? it certainly would beat dropping $750 for a new muffler.

 

Rico, I believe this was done to tune the sound so it would have a better sound.

 

If you just cut it off you would have a big hole in your exhaust.
If you cut it off and patched the hole I believe your exhaust would not be louder but it would have a horrible resonating sound at certain RPMs.