So, I took my 1999 4Runner in today due a P0420 code and bad fuel economy. The shop ran thorough tests on my sensors and then the cats and they are both bad. Prior to this, I have replaced the MAF, throttle position sensor and the upstream AF ratio sensor (not an o2 sensor). It's a California spec system, so it has 2 cats and they are both incredibly expensive. The shop quoted me $3300 P&L. I can find the parts on toyotapartszone for around $2100, but that is still quite a lot of money for a vehicle that is only worth around $7000.

I am really at a loss as to what to do. Is it worth replacing the cats? Thoughts? Experiences?