One of my catalytic converter is broken inside so that it is blocking outlet. As result the engine missfires. I have two questions. Is it necessary to replace both converters or just the one that is broken? Second, is it necessary to use original parts as replacement?

Regarding the installation how difficult is it for an average person to do the replacement or is this something better done by a muffler shop or MB dealer?

Thanks for any suggestions?

Highwater