My cat blocked up midway between Joplin, MO and Brooklyn, NY. It is the original, so I figure its time was probably up. Surprisingly, the effect was instananeous. I lost power and only barely eeked my way off the highway. My questions are these: Can I do the replacement myself? I can get either a third-party or OEM replacement -any recommendations?

Car is not drivable now. A friendly, and unnamed, mechanic punch a few holes in the old one so that I could get home. Twelve hours of bone rattling, ear splitting driving later and I'm writing this post.