Need help!!! Leak!

I need help, I was driving my car yesterday and I noticed it was making a rattling,ticking, sound at the same time this was at idle. When I would rev it up a little it would sound sort of raspy. The car seemed to be coming from right underneath the car. Ive checked underneath the car and their appears to be an exhaust leak where the y pipe connects to the back end of the exhaust. My question is, is this the reason for all this noise. Im thinking it could also be a screwed up catalytic converter making all this noise combined with the leak. My car souds like a junker when it idling, but still runs strong I still beat an lt1 and ls1 with these(my) problems.
What do you guys think it is?

just buy longtubes :) and no cats :D

I wanted to buy longtubes really bad but I live in CA and emissions laws suck around here. I also hear shorties are really not worth getting.