Any suggestions on a good brand after market manifold catalytic converter? Does anyone have experience with Bosal, Walker or Maganflow converters? Actually I already replaced converter with a Dorman brand already but it didn't last long. Check engine light back on P0420 code. Had code checked out by my dealer and firestone both shops said it's the converter. My Dorman cat is covered under replacement warranty, but I want to up grade to a better one.