[country1911]

First, try troubleshooting. Swap the downstream O2 sensors side for side, if the code changes sides, replace the sensor. If not it is the converter. You need to figure out what fried the converter. Typically this is a rich condition or misfire resulting in excess fuel in the exhaust. I recommend purchasing the entire y-pipe assembly from somewhere like rockauto.com. Replacing just a single cat would be cheaper but could be asking for issues with a cheap universal converter.