This might be a little late, but my solution to the after-cat O2 sensors is pretty low budget. After I put the LT's on, there was no bung for them in the ORY so I zip-tied the rear O2's to the transmission mount. Logically, if they are out of the increased pollutant flow, they won't detect the increased polutants. No codes for me..Then again where I live we have no emissions testing to sneak past.