During an autocross run a week and a half ago I developed an exhaust leak, just sounded a little louder and raspier than before but it's only gotten worse. Got under the car to tighten things up and found it was actually a crack 2/3rds of the way around the rear pipe coming from my Carsound 2.25" cat, and I think it's gotten even bigger than that since. It's probably a 5mm wide gash at its widest... looks like this:

__/--------\|__
__carsound|__
....\--------/|
(vertical line is the crack).

The crack is kind of next to the weld, but it's the pipe that is cracked, not the welding material. My question is:

1. Do you think this is fixable w/o getting a whole new cat? The pipe is technically part of the cat itself, but it's not through the actual convertor part of the cat.
2. How the hell could this happen? The exhaust doesn't fit horribly or anything. I'm sure the metal got quite hot on my auto-x run, but it would think it would be under a whole lot of stress to tear like that.

I'm taking it to Midas or Meineke this weekend but I just want to see if anyone's ever had this problem and if it should be fixable without getting a whole new cat my car sounds remarkably akin to a typical ricey Honda right now...