2.0L 16V/1.8L 16V swap questions

89 1.8L 16V Jetta soon to be a 2.0L 16V. I am keeping the 2.0 head for now so I need to know which catalytic converter I need. My 1.8L downpipe is cracked but the 2.0L is perfect. Can I use the 2.0 downpipe in this application and are the Cats the same for both? The 02 sensor has me wondering as well. Which one do I order or are they the same as well? Also. I'm considering ordering from AutoZone. Is this a good source? Thanks, Rick