Just wanted to share some information with the members on this forum in the event you encounter this issue. Started hearing a rattle coming from the right side of the engine bay when the car was idle. Upon further inspection on a lift I found the rattle coming from the passenger side cat. Speaking with a few different people I was advised there is a federal law which mandates that the cats come with an 8 year/80,000 mile warranty, whichever comes first. So took it to Infiniti this morning and they confirmed it, so they're covering it on that warranty. Unfortunately they're only covering the faulty one and not both. Hopefully this info will save you or someone you know some $$$ if this issue comes up.

Thanks for sharing that info.