My computer keeps tripping the 420 code (catalytic system efficiency below threshold. It tripped it years ago on a trip to Mexico and I must have gotten some Leaded gas. Then it would only trip when driving offroad slowly. No it basically stays lit after the third cat test cycle. The stealer wants $820 for one cat. I was thinking to replace both. There are some on the net for ~$220. Some say with CA emissions -Exc CA. Pretty confusing...

Anybody bought one somewhere?