I was instaling my HKS downpipe or so i thought. the exhaust removal went smooth right up to the cat. I wass like"3 bolts cant be that bad" but it can be and it was. Mazda designers made a part of the turbo heat shield wrap arround the se bolts and the O2 sensor. I also found out why my car is running rich, I have an O2 sensor in the cat but the connection is broken off!.
Anyway, once i got the heat shield out of the way, they put little aluminum curls around the sides of the bolt so you cant get a wrench arround them, so i had to pry them back. got one off, the other wasnt even there and the caused me to give up for the night. Any Ideas?

 

Sawzall or torch them off.

 

I ended up taking an angle grinder to mine...they were rusted pretty nasty.

 

cutting torch, off in 30 seconds.

 

To install my downpipe I actually just bent the heat shield so I could get the bolts on/off. A few weeks later I pushed the car and the heat right side of the heatshield shook itself off haha. The left side is still stuck on there though. It is pretty hard to get them off.