Rattling/vibrating catalytic converter

[bluestripe67]

My '01 E-320 4-Matic wagon with 75K miles is in for some MB extended warranty work. They found the noise, one of the cats is bad. The dealer says it's not covered by ANY warranty, either MB or emissions related because it's over 8 years old. Car was built Nov. '00, so that puts me about three and a half months over. Do I have any recourse by any means? If not, what are the thoughts of getting a used converter? If that's a bad idea I can buy my parts at cost and do the work myself assuming it's a unbolt/rebolt type of replacement. I haven't got under the car to see for my self yet. Appreciate the thoughts guys. Dennis