bad sounding Gsi

Hey, my exhaust on my Gsi has developed a realy bad...buzz or snap or i dont know what to call it.
The note is the same as when i got the system installed but its got this, lets call it a buzz over the top that sounds like a peewee 50 reving flat out. i noticed it as my GF drove off in the other day, it does it when its cold and when its well and truely warmed up.

The system i have is 4-2-1 headers through the stock cat and 2 1/4 thereafter through a generic muffler.

Any ideas on how the problem may be fixed? i was thinking of getting a brand name performance muffer whould this help (anyone recommend one)? The sound seems to wind up at about 2.5k.

Thanks in advance guys

get yaself a 2 1/4 highflow cat for starters cos that will fix most of the noise prob. see how ya go with that before changin the rear muffler. It makes this noise because the cat is restricting that much plus ya cat is prob old n damaged inside givin it that tin can sound.

Thanks for the advice mate

Also, check whether you have hit something and made a hole in your exhaust!

You prob got a exhaust leak mate..
I got one in my car atm and makes the noise u described.

i got a new 2 1/4 cat installed yesterday and the overall sound of the exhaust is nice and deep now but it still makes the noise though not neary as bad. Can anyone tell me how reletivly how much testing for and fixing an exhaust leak costs?

BTW. thanks GSI-PSI my old cat was stuffed.

Take it back to who ever did your exhaust and get them to fix it( if it is your exhaust)