I think I've surmised how this crack came to be. One of the original places that I went to have my catback put together, I believe removed my spring bolts and just used regular ones. I know this because there were no spring bolts, when I went to originally install the HFC in April.
Also, I had to use an exhaust donut I got from Boxer4 when I put the stocker back on; there wasn't one already on there. So it's probably a stress crack from not being able to move.
I put up a thread in the big WTB forum.... but still need something. Prefer local. OBX, used Stromung, Cobb, even stock..... If someone has something, I need it.