That suck been there done that. I cut off a o3 turbo last night the back bolt rounded on me. Talk about a pain in the a$$I just went through this Saturday. Once I got to the point your at now I just used a prybar and it came right off.
Just be careful on reinstallation. I swore I had the up pipe flange seated on the turbo and had the clamp tight yet had a major exhaust leak there. So ended up having to loosen the uppipes to get it perfect.