P0432/p0422 Aftermarket Main Cats Suggestions

I have been getting p0432/p0422 randomly the past year. With 120k miles on the car, I'm thinking it's about time the cats are due. I would like to get a metal substrate and freer flowing cat without triggering any codes.
Does anyone know what aftermarket cats that doesn't trigger codes? I've tried Magnaflow and racecats and there are no part numbers or none in stock for a 2001 clk55. I know the driver side is a pain due to the bend. Any bolt on ones vs welding ones?
Last edited by slowsky; May 9, 2012 at 04:51 PM.
http://forums.evolutionm.net/evo-how...ouler-how.html
I am buying Magnaflow 59950 and 59975 as you suggested by Marcus.
I called a shop about this and they were arguing with me that i need 4 cats not 2.
Which of the 4 cats do i tell them to replace with the parts above, the front or rear?







