Cat failure?

My 2003 E320 has 102K miles on it, and has been making a "clicking/rattle" sound that I recognized as the catalyst. I have had cars make this noise for some time prior to failure, so although I was not pleased, I figured I had awhile to deal with it. after making some noise (usually at start up & taking off from a stop) It has had three occurences of hard stumbling/power loss, lights up the check engine light. The drivability issues will continue until I turn the car off, and restart, at which time it drives normally again. When I pull the codes, it is giving misfire on cyl. 4, 5, 6. but not a "catalyst flow insufficient " code, which I would have expected. I am using a standard code scanner, as I have not yet bit the bullet on purchasing a STAR knockoff. I guess my question is for anyone who has had a cat fail, and checked the codes. Is the misfire on one bank telling me what I think it is, that the pass. side cat is plugging? I am taking her into the dealer for their diagnosis and have pre-ordered the cat (can't believe they didn't have it in stock, actually) but I would love some confirmation prior to a 1600.00 repair.

Anyone?