I've had my y-pipe (coupled with 2.5" B-Pipe, Test Pipe, and Stock Can) on for a while now and have this raspyness whenever I punch the gas and rev to about 3000rpms (Oh yeah, also runnin a INJEN intake). It's a stainless steel CM y-pipe. Fitment was perfect and I bought all new gaskets. It's not a rattle or a banging (nothing's loose). It's more or less this kinda like a bee's in can sound (although never heard to compare). It's only heard towards the front just past the flex-section on the y-pipe under accleration and this diminishes. The exhaust tone is clean and not distorted, so everything leads me to believe it's coming from the y-pipe somewhere/somehow. Is it the flex section, bad gasket, or normal since it's a lighter/thinner walled performance part? It's not too loud, I just notice it in the cabin. Any inputs would be great.

There's a pic here on page 4 of the y-pipe:
http://www.cardomain.com/memberpage/744880/4

 

Anyone ever experienced this?