Any tips out there on how to replace the oxygen sensors on an XJ8?

I fell at the first hurdle, front muffler section has to come out. The exhaust clamps are rusted onto the pipe. Got the nut off but they will not budge! I plan to to Dremel them off. How difficult is it to remove the pipes to gain access to the sensors? The converters look "delicate" and I don't want to bang on them too much in case they crack. The Mapp torch will probably come into play. The rest looks doable though the electrical connectors are in an awkward position behind the throttle body.