I checked gasket between y-pipe and cat converter and even installed a new one and "VW beetle noise" is still there!
Now I can say for sure that noise is coming from the flex section, because there is no inner braided liner just like on the outside of the flex section (I checked it before installation and it wasn't there). “VW noise” is caused by exhaust gas turbulence in the flex section. I e-mailed Jody at Budget Performance Exhaust regarding this problem and asked her if it's possible to exchange my y-pipe for a new one, otherwise I will have to cut this noisy flex section and replace it with a good one, no other options here.

 

There isn't supposed to be braided liner on the inside. Budget doesn't use a lined flex. They tried lined flex joints and wound up with the same problems as Cattman. I don't know why you are getting that noise but its not typical of Budget pipes, at least not mine or any others I have listened to.

 

This lined flex section has an inner braided liner just like the outside of the flex section.

WarpSpeed Performance "Through testing we have discovered that one can almost totally eliminate the hiss or bees in a can sound of the flex section on our and the other Y pipes by installing a lined flex section."

 

I have the same noise that MAX95RUS is experiencing. The noise isn't loud at all and i can only hear it when the radio/ac is off and all the windows are rolled up. Let me know if you find any solutions.