It does help to move the exhaust on a tranny swap...I made a habit of taking the entire exhaust loose at the header and removing it...sure made for a lot less headache. I soaked the studs with PB Blaster for several days prior to removal...re-soaked them daily until it was time to break them loose. Didn't break the studs, and used anti-seize on reassembly. After that, I never had an issue. It helps to clean the threads up once you get the DP off with a drill mounted wire brush.

G'luck...and if you do break something, I've had much success getting parts from Tom at Parts Group.