If you've researched this you know that many things can cause P0420, exhaust leak, faulty primary O2 sensor, faulty secondary o2 sensor, or damaged catalytic converter.
Suggest reviewing ericthecarguy, briansmoble1, and scottykilmer videos on this subject.
The Acura/Honda converters are good, so I would want to first be sure it wasn't something else before replacing.
2003 Acura MDX w/ Nav
2006 Acura TSX
2010 Acura TSX
1994 Honda Accord
See you down the ROW!