[V6-12v] Experience changing cats

[The CyberPoet]

Although I don't have any useful advice specific to getting the nuts  
out, I do have some advice for when you go to reassemble it:
Always coat any bolt or male fastener on the exhaust side of the  
engine with high-temp anti-seize before reassembling it.
This advice also applies to rear wheel lugs, where a stuck e-brake  
can overheat the brakes (and thus the lugs).

Good Luck!
=-= Marc Glasgow