Sam, a Dremel is an important part of your auto repair arsenel.
But next time, you should assume all exhaust system components will be held together by seized fasteners. Soak overnight with WD-40 or PB Blaster. Use 6-point sockets & wrenches if you have them. I think it's easier to slip / round off nuts and bolts using 12-pt tools. Finally, use anti-seize lubricant on the threads when you assemble these components so next time will be easier. Sorry for the long-winded response, Sam!
Enjoying the weather here?