2000 Blazer Converter issues

Hola, I've got a 2000 Chevy Blazer 2 door 4.3L RWD, and I'm getting the SES light thrown at me :shakehead So I took my car to my local mechanic and asked him to check the codes and see what was wrong, he told me it was the cat converter. They cleared the codes for me, but it didn't take long for the SES light to come back. Anyways, I'm getting about 15mpg which really isn't all that great and my exhaust system sounds like CRAP! I've looked on summit and jegs and am unable to find a cat, I've found plenty of cat-back systems, which I will be purchasing, but is not what I need immediately. Any help is appreciated. Thanks.

summit and jegs should have universal catco or magnaflow cats for around $60. you can also find them cheaper on ebay. you will have to have someone weld it in for you.

There are several DTC's, (Diagnostic Trouble Codes) that pertain to the catalytic converter. Not all of them require converter replacement. There are no DTC's that say "replace the converter". What code was retrieved from the ODBII? What diagnostics were performed to determine the converter was faulty?

The converter is phsyically falling apart, I crawled under it about a week ago, and it's rapidly deteriorating. It sounds absolutely horrible. I'm just going to have a muffler shop set me up with a high flow cat, and a nice cat back system. I just don't want to have backpressure issues though and lose my bottom end. Any suggestions? the only thing I could find on summit is a Gibson side swept system and that was a little pricey.