Originally posted by qtiger
You could, but I personally wouldn't buy a used cat. That's just buying used spark plugs.
Install y8 header, y8 style cat. Rewire and extend engine harness for 4-wire HO2 sensor.
You will also need to modify your current exhaust system as undoubtedly it'll be too long.
Don't the EX,LX,DX use the same pri. & sec. O2 sensors, just in different places on the manifold (because of the different cat positions)?