just read this article:
Howstuffworks "How do I know if my catalytic converter has failed?"
an excerpt from it:
Any additives or malfunctions that cause the mixture or the temperature of the exhaust gases to change reduce the effectiveness and life of the catalytic converter. Leaded gasoline and the over-use of certain fuel additives can shorten the life of a catalytic converter.
so , make sure premium fuel you may use does not harm your catcon.
credit for providing link goes to the member: greatmana2000