In this video I am replacing primary catalytic converters on my 2006 Nissan Xterra with factory ones. I have purchased the truck with the check engine light on. The codes were P0420 and P0430 both primary catalytic converters not functioning properly. The truck ran and idled fine, but the exhaust smelled of raw gas and sounded raspy. In the process of removal the old cats I discovered that the previous owner has had them hollowed out. I wish I knew this prior to ordering and buying the new factory cats ($1,100 after a discount) as I would have just left those in place. Second thought, the exhaust sounds like stock now and there is no nasty smell from exhaust when the truck idles upon cold start. Overall, I am happy that I did this job as I have saved about $1,000 on labor/installation costs. It took me about 1.5 hours to do each side, so 34 hours total while filming.
I hope you'll find this video helpful if you are considering replacing your cats on a Nissan truck!