2003 Malibu exhaust flange stud removal to get cat off

I have a 2003 Malibu, 167k, v6, 3.1 auto. My hope is to replace the whole exhaust but can't get the exhaust manifold to cat pipe removed. These are two standard GM type studs - threads on both ends. I've soaked in oil/PB/... with no luck and the studs are too out of the way to place a flame on. So how do I remove them? There has to be a secret to this. Thanks.

 

One picture is worth thousand words....

You need to remove studs or nuts on studs?
If studs, then you want to remove shorter stud thread out of whatever it is in?
Do you have long stud thread exposed?
1. Does it have hex or Torx head? As then socket can be used on it.
2. If not, and stud is sticking out of whatever about and inch, put a nut on and then a second nut on top of that one, flush. Tighten them together. Then use first nut as one to twist stud out. As spanner won't work on it, you'll strip the nut, I'd use good visegrip. Sometimes those nuts align just just right so that you can slide a box wrench onto the first nut. That's best. Then a prayer and cheat pipe.
Be prepared to stud snap. They are overheated and snap easy.