Hello,
Did you every resolve your Cat issue? I'm facing the same problem with my '00 4-Runner. The Check Engine light has been on for almost 2 years and Dealer says both Cats are throwing Codes and need replaced (almost $2500 for OEM parts). I've replaced both O2 Sensors and will be replacing the MAF Sensor in the near future. I'm in East Orlando, so if you know of a local shops to fix the Cat problem, please let me know.
Thanks.
Chris