Exhaust bolts remove/replace ?

I was wondering what everyone does with the three exhaust bolts that connect the twin minicat piece to the rest of the exhaust. I haven't touched them yet but the bolts are SO thin and rusted there is absolutely no way I can imagine them coming off without taking a cutoff wheel or something to them. Suggestions other than cutoff wheel or is it as good as any?

So once things are apart, what is the best way to put them back together again? I'm guessing drill out the holes (assuming I can identify them ) and bolt and nut but just wanted to make certain there were no wiser ways. (and I hate drilling rusty bolts out of holes)

Try to remove them. If they break anyways, you don't have to setup the grinder. Just a standard bolt will work, antiseize them, but it won't matter they will heat and cool and eventually become what they are right now. Just my take.

Jeff