Any suggestions? It is pretty rusty around the bolts...I tried penetrating oil, but no luck. Any other suggestions?

 

Heat the bolts up with a propane torch perhaps, and try again.

 

did you apply penetrating oil the day before

Apply Liquid Wrench right now, tomorrow try again.

 

To Get my stillen on I had to cut the nut and bolt on the rear side and then punch the welded nut through the front side. Painful and time consuming but the exhaust was fine...A torch would be the best way to do it though