You can look up the OEM part number on OEMAcuraparts.com for the downstream/upstream sensor and cross reference that with the part numbers on RockAuto's site. O2 sensors are found under the Emissions submenu on RA's website.
Put it in with a bit, a very small drop, of anti-sieze on only the threads. You'll probly need a giant wrench to pull it, this should make it easier if you ever have a problem again.
and I clarified my dude,for engine 2.3 I4 F23A1, Denso Oxygen Sensor # 234-4620 is for the front up, before the cat and Oxygen Sensor Denso 234-4209 is down after the cat