Striped Bolt(2 questions)
 

I striped the nut on the Catalitic Coverter
on the downpipe side. Any good ways to
take it off with out cutting.

Another thing how does one take the O2
sensor out of the downpipe?

pry or pull on the nut as you turn it off it may catch hold and back off . Garfinkle changed my sensor with a deep well socket ,he folded the wire down and outside the socket ,on problem

Thanks

you can always drill it out .